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Contents

The "standard dictionary numbers"

Usage of names of large numbers

Adam, Chuquet and the origins of the "standard dictionary numbers"

An ''aide-memoire''

The googol family

Extensions of the standard dictionary numbers

Other large numbers used in mathematics

See also

External links

References

The "standard dictionary numbers"

Throughout this article, exponential or scientific notation is used. 10⁶ could also be written as the number 1 followed by six 0s, 1 000 000; 10⁹ could be written as 1 000 000 000; and so on.
Names of numbers larger than a quadrillion are almost never used, for reasons discussed further below. It is debatable which of them should be considered real working English vocabulary and which are merely trivia, curiosities, or coinages. The following table lists those names of numbers which are found in many English dictionaries and thus have a special claim to being "real words". The "Traditional British" values shown are unused in American English and are becoming obsolete in British English, but are dominant in many non-English-speaking areas, including continental Europe and Spanish-speaking countries in Latin America; see Long and short scales.

Name	Short scale (USA and Modern British)	Long scale (Traditional British)	Authorities
			AHD4[1]	COD[2]	OED2[3]	OEDnew[4]	RHD2[5]	SOED3[6]	W3[7]	UM[8]
million	106	106								Not verified whether this term is mentioned in this work of reference
milliard		109
billion	109	1012
billiard		1015
trillion	1012	1018
trilliard		1021
quadrillion	1015	1024
quintillion	1018	1030
sextillion	1021	1036
septillion	1024	1042
octillion	1027	1048
nonillion	1030	1054
decillion	1033	1060
undecillion	1036	1066
duodecillion	1039	1072
tredecillion	1042	1078
quattuordecillion	1045	1084
quindecillion (quinquadecillion)	1048	1090
sexdecillion (sedecillion)	1051	1096
septendecillion	1054	10102
octodecillion	1057	10108
novemdecillion (novendecillion)	1060	10114
vigintillion	1063	10120
googol	10100	10100
centillion	10303	10600
googolplex	1010100	1010100
Skewes' number	1.39822 × 10316

''Centillion''^[9] appears to be the highest name ending in -illion that is included in these dictionaries. ''Trigintillion'', often cited as a word in discussions of names of large numbers, is not included in any of them, nor are any of the names that can easily be created by extending the naming pattern (''unvigintillion'', ''duovigintillion'', ''duoquinquagintillion'', etc.).
All of the dictionaries included ''googol'' and ''googolplex'', generally crediting it to the Kasner and Newman book and to Kasner's nephew. None include any higher names in the googol family (googolduplex, etc.). The Shorter Oxford English Dictionary comments that ''googol'' and ''googolplex'' are "not in formal mathematical use".

★ In the book ''Fast Food Nation'', author Eric Schlosser claims a Geographic Information System named "Quintillion" is used by McDonald's to analyze data to help predict a new location for one of its restaurants. According to Schlosser, Quintillion uses data such as satellite photos, income, new housing plans, and road layouts to predict future incomes and population patterns. (Page 66 of the 2002 European paperback edition).

★ ''Vigintillion'' is used by H. P. Lovecraft in his short story The Call of Cthulhu.

Usage of names of large numbers

Some large numbers have real referents in human experience, and their names are encountered in many contexts. For example, on one day in 2004, Google News showed 78 600 hits on ''billion'', starting with "Turkey Repays USD 1.6 Billion In Foreign Debt". It showed 9870 hits on ''trillion'' and 56 on ''quadrillion'': for example, "The US Department of Energy reports that in 2002, the United States economy consumed 97.6 quadrillion BTUs (quad BTUs)."
Names of larger numbers, however, have a tenuous, artificial existence. Although they may be found in dictionaries, these names are rarely found outside definitions, lists, and discussions of the ways in which large numbers are named. Even well-established names like ''sextillion'' are rarely used, since in the contexts of science, astronomy, and engineering, where large numbers often occur, numbers are usually written using ''scientific notation''. In this notation, used since the 1800s, powers of ten are expressed as ''10'' with a numeric superscript, e.g., "The X-ray emission of the radio galaxy is 1.3·10⁴⁵ ergs." When a number such as 10⁴⁵ needs to be referred to in words, it is simply read out: "ten to the forty-fifth." This is just as easy to say, easier to understand, and less ambiguous than "quattuordecillion" (which means something different in the long scale and the short scale). When a number represents a quantity rather than a count, SI prefixes can be used; one says "femtosecond", not "one quadrillionth of a second", although often powers of ten are used instead of some of the very high and very low prefixes. In some cases, specialized units are used, such as the astronomer's parsec and light year or the particle physicist's barn.
Nevertheless, large numbers have an intellectual fascination and are of mathematical interest, and giving them names is one of the ways in which people try to conceptualize and understand them.
One of the first examples of this is ''The Sand Reckoner'', in which Archimedes gave a system for naming large numbers. To do this, he called the numbers up to a myriad myriad (10⁸) "first numbers" and called 10⁸ itself the "unit of the second numbers". Multiples of this unit then became the second numbers, up to this unit taken a myriad myriad times, 10⁸·10⁸=10¹⁶. This became the "unit of the third numbers", whose multiples were the third numbers, and so on. Archimedes continued naming numbers in this way up to a myriad myriad times the unit of the 10⁸-th numbers, i.e., $(10^8)^\{(10^8)\}=10^\{8cdot\; 10^8\},$ and embedded this construction within another copy of itself to produce names for numbers up to $left((10^8)^\{(10^8)\}$
ight)^{(10^8)}=10^{8cdot 10^{16}}. Archimedes then estimated the number of grains of sand that would be required to fill the known Universe, and found that it was no more than "one thousand myriad of the eighth numbers" (10⁶³.)
Since then, many others have engaged in the pursuit of conceptualizing and naming numbers that really have no existence outside of the imagination. One motivation for such a pursuit is that attributed to the inventor of the word ''googol'', who was certain that any finite number "had to have a name". Another possible motivation is competition between students in computer programming courses, where a common exercise is that of writing a program to output numbers in the form of English words.
It should be noted, too, that most names proposed for large numbers belong to systematic schemes which are extensible. Thus, many names for large numbers are simply the result of following a naming system to its logical conclusion—or extending it further.
In this article, we present some names that have been given to large numbers, and the context and authority for the names. These numbers are almost pure mathematical abstractions, not physical realities. The names for such numbers are very rarely used. They may have a claim staked out for them in reference books, but they remain more in the nature of curiosities, trivia, or mathematical recreation than genuine working English vocabulary.

Adam, Chuquet and the origins of the "standard dictionary numbers"

The words ''bymillion'' and ''trimillion'' were first recorded in 1475 in a manuscript of Jehan Adam. Subsequently, Nicolas Chuquet wrote a book ''Triparty en la science des nombres'' which was not published during Chuquet's lifetime. However, most of it was copied by Estienne de La Roche for a portion of his 1520 book, ''L'arismetique''. Chuquet's book contains a passage in which he shows a large number marked off into groups of six digits, with the comment:

Ou qui veult le premier point peult signiffier million Le second point byllion Le tiers poit tryllion Le quart quadrillion Le cinq^e quyllion Le six^e sixlion Le sept.^e septyllion Le huyt^e ottyllion Le neuf^e nonyllion et ainsi des ault'^s se plus oultre on vouloit preceder

(Or if you prefer the first mark can signify million, the second mark byllion, the third mark tryllion, the fourth quadrillion, the fifth quyillion, the sixth sixlion, the seventh septyllion, the eighth ottyllion, the ninth nonyllion and so on with others as far as you wish to go).

Chuquet is sometimes credited with inventing the names ''million'', ''billion'', ''trillion'', ''quadrillion'', and so forth. This is an oversimplification.

★ ''Million'' was certainly not invented by Adam or Chuquet. ''Milion'' is an Old French word thought to derive from Old Italian ''milione'', an intensification of ''mille'', a thousand. That is, a ''million'' is a ''big thousand'', much as 1728 is a ''great gross''.

★ From the way in which Adam and Chuquet use the words, it can be inferred that they were recording usage rather than inventing it. One obvious possibility is that words similar to ''billion'' and ''trillion'' were already in use and well-known, but that Chuquet, an expert in exponentiation, extended the naming scheme and invented the names for the higher powers.

★ Notice that Chuquet's names are only similar to, not identical to, the modern ones.
Adam and Chuquet used the long scale of powers of a million; that is, Adam's ''bymillion'' (Chuquet's ''byllion'') denoted 10¹², and Adam's ''trimillion'' (Chuquet's ''tryllion'') denoted 10¹⁸.

An ''aide-memoire''

An easy way to find the value of the above numbers in the short scale is to take the number indicated by the prefix (such as 2 in ''bi''llion, 4 in ''quadri''llion, 18 in ''octodec''illion, etc.), add one to it, and multiply that result by 3. For example, in a trillion, the prefix is ''tri'', meaning 3. Adding 1 to it gives 4. Now multiplying 4 by 3 gives us 12, which is the power to which 10 is to be raised to express a short-scale trillion in scientific notation: one trillion = 10¹².
In the long scales, this is done simply by multiplying the number from the prefix by 6. For example, in a billion, the prefix is ''bi'', meaning 2. Multiplying 2 by 6 gives us 12, which is the power to which 10 is to be raised to express a long-scale billion in scientific notation: one billion = 10¹².
These mechanisms are illustrated in the table in long and short scales.

The googol family

The names ''googol'' and ''googolplex'' were invented by Edward Kasner's nephew, Milton Sirotta, and introduced in Kasner and Newman's 1940 book,
''Mathematics and the Imagination,''^[10]
in the following passage:

Words of wisdom are spoken by children at least as often as by scientists. The name "googol" was invented by a child (Dr. Kasner's nine-year-old nephew) who was asked to think up a name for a very big number, namely 1 with a hundred zeroes after it. He was very certain that this number was not infinite, and therefore equally certain that it had to have a name. At the same time that he suggested "googol" he gave a name for a still larger number: "Googolplex". A googolplex is much larger than a googol, but is still finite, as the inventor of the name was quick to point out. It was first suggested that a googolplex should be 1, followed by writing zeros until you got tired. This is a description of what would actually happen if one actually tried to write a googolplex, but different people get tired at different times and it would never do to have Carnera a better mathematician than Dr. Einstein, simply because he had more endurance. The googolplex is, then, a specific finite number, with so many zeros after the 1 that the number of zeros is a googol.

{|class="prettytable"
! width=200 | Value
! Name
! Authority
|-
| 10¹⁰⁰ || Googol || Kasner and Newman, dictionaries (see above)
|-
| 10^googol = $,!10^\{10^\{100\}\}$ || Googolplex || Kasner and Newman, dictionaries (see above)
|}
Conway and Guy ''The Book of Numbers'', J. H. Conway and R. K. Guy, New York: Springer-Verlag, 1996, pp. 15–16. ISBN 0-387-97993-X.
have suggested that ''N-plex'' be used as a name for 10^N. This gives rise to the name ''googolplexplex'' for 10^googolplex; however, the word ''googleplexian'' is given by one site. In addition, the terms ''googolduplex'', ''googoltriplex'', etc. have been coined by various persons for the numbers 10^googolplex, 10^googolduplex, etc. Conway and Guy have proposed that ''N-minex'' be used as a name for 10^-N, giving rise to the name ''googolminex'' for the reciprocal of a googolplex. None of these names are in wide use, nor are any currently found in dictionaries.

Extensions of the standard dictionary numbers

This table illustrates several systems for naming large numbers, and shows how they can be extended past decillion.
Traditional British usage assigned new names for each power of one million (the long scale): 1000000 = 1 million, 1000000² = 1 billion, 1000000³ = 1 trillion and so on. It was adapted from French usage, and is similar to the system that was documented or invented by Chuquet.
Traditional American usage (which, oddly enough, was also adapted from French usage but at a later date), and modern British usage, assigns new names for each power of one thousand (the short scale.) Thus, a ''billion'' is 1000 · 1000² = 10⁹, a ''trillion'' is 1000 · 1000³ = 10¹², and so forth. Due to its dominance in the financial world (and by the US-dollar) this was adopted for official United Nations documents.
Traditional French usage has varied; in 1948 , France, which had been using the short scale, reverted to the long scale.
The term ''milliard'' is unambiguous and always means 10⁹. It is almost never seen in American usage, rarely in British usage, and frequently in European usage. The term is sometimes attributed to a French mathematician named Jacques Peletier du Mans circa 1550 (for this reason, the long scale is also known as the ''Chuquet-Peletier'' system), but the Oxford English Dictionary states that the term derives from post-Classical Latin term ''milliartum'', which became ''milliare'' and then ''milliart'' and finally our modern term.
With regard to names ending in -illiard for numbers 10^6·n+3, ''milliard'' is certainly in widespread use in languages other than English, but the degree of actual use of the larger terms is questionable. For example, as of 2004, Google searches on French-language pages for ''trillion'', ''quadrillion'', and ''quintillion'' return 6630, 312, and 127 hits respectively, whilst searches for ''trilliard'' and ''quadrilliard'' return only 102 and 7 hits respectively. However, one has to take into account that these large numbers are not often needed and that scientists almost always use scientific notation. In German the terms "Milliarde", "Billiarde" etc. are out of question.
'Names of reciprocals of large numbers' do not need to be listed here, because they are regularly formed by adding -th, e.g. ''quattuordecillionth,'' ''centillionth,'' etc.
For additional details, see Billion (disambiguation) and long and short scales.
{| class="prettytable"
!Value
! U.S. and modern British
(short scale)
!Traditional British
(long scale)
!Traditional European (Pelletier)
(long scale)
|-
|10⁶ || Million || Million || Million
|-
|10⁹ || Billion || Thousand million || Milliard
|-
|10¹² || Trillion || Billion || Billion
|-
|10¹⁵ || Quadrillion || Thousand billion || Billiard
|-
|10¹⁸ || Quintillion|| Trillion || Trillion
|-
|10²¹ || Sextillion || Thousand trillion || Trilliard
|-
|10²⁴ || Septillion || Quadrillion || Quadrillion
|-
|10²⁷ || Octillion] || Thousand quadrillion || Quadrilliard
|-
|10³⁰ || Nonillion || Quintillion || Quintillion
|-
|10³³ || Decillion || Thousand quintillion || Quintilliard
|-
|10³⁶ || Undecillion || Sextillion || Sextillion
|-
|10³⁹ || Duodecillion || Thousand sextillion || Sextilliard
|-
|10⁴² || Tredecillion || Septillion || Septillion
|-
|10⁴⁵ || Quattuordecillion || Thousand septillion || Septilliard
|-
|10⁴⁸ || Quindecillion || Octillion || Octillion
|-
|10⁵¹ || Sexdecillion || Thousand octillion || Octilliard
|-
|10⁵⁴ || Septendecillion || Nonillion || Nonillion
|-
|10⁵⁷ || Octodecillion || Thousand nonillion || Nonilliard
|-
|10⁶⁰ || Novemdecillion || Decillion || Decillion
|-
|10⁶³ || Vigintillion || Thousand decillion || Decilliard
|-
|10⁶⁶ || Unvigintillion || Undecillion || Undecillion
|-
|10⁶⁹ || Duovigintillion || Thousand undecillion || Undecilliard
|-
|10⁷² || Trevigintillion || Duodecillion || Duodecillion
|-
|10⁷⁵ || Quattuorvigintillion || Thousand duodecillion || Duodecilliard
|-
|10⁷⁸ || Quinvigintillion || Tredecillion || Tredecillion
|-
|10⁸¹ || Sexvigintillion || Thousand tredecillion || Tredecilliard
|-
|10⁸⁴ || Septenvigintillion || Quattuordecillion || Quattuordecillion
|-
|10⁸⁷ || Octovigintillion || Thousand quattuordecillion || Quattuordecilliard
|-
|10⁹⁰ || Novemvigintillion || Quindecillion || Quindecillion
|-
|10⁹³ || Trigintillion || Thousand quindecillion || Quindecilliard
|-
|10⁹⁶ || Untrigintillion || Sexdecillion || Sexdecillion
|-
|10⁹⁹ || Duotrigintillion || Thousand sexdecillion || Sexdecilliard
|-
|10¹⁰⁰ || Ten duotrigintillion || Ten thousand sexdecillion || Ten sexdecilliard
|-
|10¹⁰² || Tretrigintillion || Septendecillion || Septendecillion
|-
|10¹⁰⁵ || Quattuortrigintillion || Thousand septendecillion || Septendecilliard
|-
|10¹⁰⁸ || Quintrigintillion || Octodecillion || Octodecillion
|-
|10¹¹¹ || Sextrigintillion || Thousand octodecillion || Octodecilliard
|-
|10¹¹⁴ || Septentrigintillion || Novemdecillion || Novemdecillion
|-
|10¹¹⁷ || Octotrigintillion || Thousand novemdecillion || Novemdecilliard
|-
|10¹²⁰ || Novemtrigintillion || Vigintillion || Vigintillion
|-
|10¹²³ || Quadragintillion || Thousand vigintillion || Vigintilliard
|-
|10¹²⁶ || Unquadragintillion || Unvigintillion || Unvigintillion
|-
|10¹²⁹ || Duoquadragintillion || Thousand unvigintillion || Unvigintilliard
|-
|10¹³² || Trequadragintillion || Duovigintillion || Duovigintillion
|-
|10¹³⁵ || Quattuorquadragintillion || Thousand duovigintillion || Duovigintilliard
|-
|10¹³⁸ || Quintoquadragintillion || Trevigintillion || Trevigintillion
|-
|10¹⁴¹ || Sexquadragintillion || Thousand trevigintillion || Trevigintilliard
|-
|10¹⁴⁴ || Septenquadragintillion || Quattuorvigintillion || Quattuorvigintillion
|-
|10¹⁴⁷ || Octoquadragintillion || Thousand quattuorvigintillion || Quattuorvigintilliard
|-
|10¹⁵⁰ || Novemquadragintillion || Quinvigintillion || Quinvigintillion
|-
|10¹⁵³ || Quinquagintillion || Thousand quinvigintillion || Quinvigintilliard
|-
|10¹⁵⁶ || Unquinquagintillion || Sexvigintillion || Sexvigintillion
|-
|10¹⁵⁹ || Duoquinquagintillion || Thousand sexvigintillion || Sexvigintilliard
|-
|10¹⁶² || Trequinquagintillion || Septenvigintillion || Septenvigintillion
|-
|10¹⁶⁵ || Quattuorquinquagintillion || Thousand septenvigintillion || Septenvigintilliard
|-
|10¹⁶⁸ || Quinquinquagintillion || Octovigintillion || Octovigintillion
|-
|10¹⁷¹ || Sexquinquagintillion || Thousand octovigintillion || Octovigintilliard
|-
|10¹⁷⁴ || Septenquinquagintillion || Novemvigintillion || Novemvigintillion
|-
|10¹⁷⁷ || Octoquinquagintillion || Thousand novemvigintillion || Novemvigintilliard
|-
|10¹⁸⁰ || Novemquinquagintillion || Trigintillion || Trigintillion
|-
|10¹⁸³ || Sexagintillion || Thousand trigintillion || Trigintilliard
|-
|10¹⁸⁶ || Unsexagintillion || ... || ...
|-
|10¹⁸⁹ || Duosexagintillion || ... || ...
|-
|10¹⁹² || Tresexagintillion || ... || ...
|-
|10¹⁹⁵ || Quattuorsexagintillion || ... || ...
|-
|10¹⁹⁸ || Quinsexagintillion || ... || ...
|-
|10²⁰¹ || Sexsexagintillion|| ... || ...
|-
|10²⁰⁴ || Septsexagintillion || ... || ...
|-
|10²⁰⁷ || Octosexagintillion || ... || ...
|-
|10²¹⁰ || Novemsexagintillion || ... || ...
|-
|10²¹³ || Septuagintillion || Thousand quintrigintillion || Quintrigintilliard
|-
|10²¹⁶ || Unseptuagintillion || ... || ...
|-
|10²¹⁹ || Duoseptuagintillion || ... || ...
|-
|10²²² || Treseptuagintillion || ... || ...
|-
|10²²⁵ || Quattuorseptuagintillion || ... || ...
|-
|10²²⁸ || Quinseptuagintillion || ... || ...
|-
|10²³¹ || Sexseptuagintillion || ... || ...
|-
|10²³⁴ || Septseptuagintillion || ... || ...
|-
|10²³⁷ || Octoseptuagintillion || ... || ...
|-
|10²⁴⁰ || Novemseptuagintillion || Quadragintillion || Quadragintillion
|-
|10²⁴³ || Octogintillion || Thousand quadragintillion || Quadragintilliard
|-
|10²⁴⁶ || Unoctogintillion || ... || ...
|-
|10²⁴⁹ || Duooctogintillion || ... || ...
|-
|10²⁵² || Treoctogintillion || ... || ...
|-
|10²⁵⁵ || Quattuoroctogintillion || ... || ...
|-
|10²⁵⁸ || Quinoctogintillion || ... || ...
|-
|10²⁶¹ || Sexoctogintillion || ... || ...
|-
|10²⁶⁴ || Septoctogintillion || ... || ...
|-
|10²⁶⁷ || Octooctogintillion || ... || ...
|-
|10²⁷⁰ || Novemoctogintillion || Quinquadragintillion || Quinquadragintillion
|-
|10²⁷³ || Nonagintillion || Thousand Quinquadragintillion || Quinquadragintilliard
|-
|10²⁷⁶ || Unnonagintillion || ... || ...
|-
|10²⁷⁹ || Duononagintillion || ... || ...
|-
|10²⁸² || Trenonagintillion || ... || ...
|-
|10²⁸⁵ || Quattuornonagintillion || ... || ...
|-
|10²⁸⁸ || Quinnonagintillion || ... || ...
|-
|10²⁹¹ || Sexnonagintillion || ... || ...
|-
|10²⁹⁴ || Septnonagintillion || ... || ...
|-
|10²⁹⁷ || Octononagintillion || ... || ...
|-
|10³⁰⁰ || Novemnonagintillion || Quinquagintillion || Quinquagintillion
|-
|10³⁰³ || Centillion || Thousand quinquagintillion || Quinquagintilliard
|-
|10³⁰⁶ || Cenuntillion || ... || ...
|-
|10³⁰⁹ || Cendotillion || ... || ...
|-
|10³¹² || Centretillion || ... || ...
|-
|10³⁶⁰ || Cennovemdecillion || Sexagintillion || Sexagintillion
|-
|10³⁶³ || Cenvigintillion || Thousand sexagintillion || Sexagintilliard
|-
|10⁴²⁰ || Cennovemtrigintillion || Septuagintillion || Septuagintillion
|-
|10⁴²³ || Cenquadragintillion || Thousand septuagintillion || Septuagintilliard
|-
|10⁴⁸⁰ || Cennovemquinquagintillion || Octogintillion || Octogintillion
|-
|10⁴⁸³ || Censexagintillion || Thousand octogintillion || Octogintilliard
|-
|10⁵⁴⁰ || Cennovemseptuagintillion || Nonagintillion || Nonagintillion
|-
|10⁵⁴³ || Cenoctogintillion || Thousand nonagintillion || Nonagintilliard
|-
|10⁶⁰⁰ || Cennovemnonagintillion || Centillion || Centillion
|-
|10⁶⁰³ || Ducentillion || Thousand centillion || Centilliard
|-
|10⁹⁰³ || Trecentillion || ... || ...
|-
|10¹²⁰³ || Quadringentillion || ... || ..
|-
|10¹⁵⁰³ || Quingentillion || ... || ...
|-
|10¹⁸⁰³ || Sescentillion || ... || ...
|-
|10²¹⁰³ || Septingentillion || ... || ...
|-
|10²⁴⁰³ || Octingentillion || Thousand quadringentillion || Quadringentilliard
|-
|10²⁷⁰³ || Nongentillion || Thousand quadringentiquinquagintillion || Quadringentiquinquagintilliard
|-
|10³⁰⁰³ || Millillion || Thousand quingentillion || Quingentilliard
|-
|10¹⁰¹⁰⁰ || Googolplex || ... || ...
|-
|10^googolplex || Googolplexian || ... || ...
|-
|}
The system of using Latin prefixes will become ambiguous for numbers with exponents of a size which the Romans rarely counted to, like 10^6,000,258. John Horton Conway and Richard Guy have proposed a consistent set of conventions which permit the system to provide "English names", in principle, for any integer whatever.

Other large numbers used in mathematics

★ Skewes' number

★ Avogadro's number

★ Graham's number

★ Steinhaus–Moser notation

See also

★ List of numbers

★ Large numbers

★ Long and short scales

★ Nicolas Chuquet

★ Jacques Peletier du Mans

★ Indian numbering system

★ Orders of magnitude

★ Knuth

★ SI prefix

★ Billion

★ Indefinite and fictitious numbers

★ Zillion

★ Crore

External links

★ Large Numbers article by Robert Munafo

★ ''How high can you count?'' by Landon Curt Noll.

★ Full list of large number names list sorted by 10ⁿ and by word length

★ Big numbers Educational site, which can name any numbers put into it (up to centillion)

References

1. ''American Heritage Dictionary'', 4th edition, ISBN 0-395-82517-2. [1]
2. Cambridge Dictionaries Online, Cambridge, UK: Cambridge University Press.
3. ''Oxford English Dictionary'', 2nd edition, Oxford, UK: Oxford University Press. ISBN 0198611862 (and addendums since publication in 1989.)
4. ''Oxford English Dictionary'', New Edition, Oxford, UK: Oxford University Press. [2] (subscription required), checked April 2007
5. ''The Random House Dictionary'', 2nd Unabridged Edition, 1987, Random House.
6. ''Shorter Oxford English Dictionary'', 3rd edition, 1993, Oxford: Clarendon Press.
7. ''Webster's Third New International Dictionary, Unabridged'', 1993, Merriam-Webster.
8. ''How Many? A Dictionary of Units of Measures''
9. Entry for ''centillion'' in the ''American Heritage Dictionary''
10. Kasner, Edward and James Newman, ''Mathematics and the Imagination,'' 1940, Simon and Schuster, New York.