# Names of large numbers

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Naming very large numbers is relatively easy. There are two main ways of naming a number: scientific notation and naming by grouping. For example, the number 500,000,000,000,000,000,000 can be called 5 × 1020 in scientific notation since there are 20 zeros behind the 5. If the number is named by grouping, it is five hundred quintillion (American) or 500 trillion (European).

When large numbers have many different decimals in them, such as 642 500 000 000, naming them with scientific notation is about the same, but with one difference. Still counting the number of numbers after the first number (in this case, after the 6 there are 11 numbers) you need to include the ones that are not zero in the formula, but after a decimal point. So 642 500 000 000 will be 6.425 × 1011. When naming by grouping, each group is the name of the group. With the same number, it would be said to be 642 billion, 500 million (US) or 642 milliard, 500 million (Eur).

## Some examples

Number Scientific notation Grouping
6e+26 6 × 1026 600 septillion (quadrillion)
765 476 250 000 000 7.6547625 × 1014 765 trillion, 476 billion, 250 million
145 000 1.45 × 105 145 thousand

## Forms of numbering

The American way or "Short form" for naming large numbers is different from the European way or "Long form" of naming large numbers. This is mainly because of American finance. Short form numbering is based on thousands and Long form is based on millions. Because of this, in Short form a billion is one thousand millions (109) while in Long form it is one million millions (1012). The change in the United Kingdom to Short form numbering happened in 1974. Today, Short form is most commonly used in most English speaking countries.

## Names for large numbers

Scientific
notation
American name

(Short Form)

Old European name

(Long Form)

Old-British name SI Symbol Metric prefix
1 One One One
10 Ten Ten Ten da Deca-
100 Hundred Hundred Hundred h Hecto-
1000 Thousand Thousand Thousand k Kilo-
10000 Ten thousand Ten thousand Ten thousand my (Now obsolete) Myria- (Now obsolete)
100000 Hundred thousand Hundred thousand Hundred thousand
1000000 Million Million Million M Mega-
1000000000 Billion Milliard Thousand million G Giga-
1012 Trillion Billion Billion T Tera-
1015 Quadrillion Billiard Thousand billion P Peta-
1018 Quintillion Trillion Trillion E Exa-
1021 Sextillion Trilliard Thousand trillion Z Zetta-
1027 Octillion Quadrilliard Thousand quadrillion R Ronna-
1030 Nonillion Quintilion Quintillion Q Quetta-
1033 Decillion Quintilliard Thousand quintillion
1036 Undecillion Sextillion Sextillion
1039 Duodecillion Sextilliard Thousand sextillion
1042 Tredecillion Septillion Septillion
1045 Quattuordecillion Septilliard Thousand septillion
1048 Quindecillion Octillion Octillion
1051 Sexdecillion Octilliard Thousand octillion
1054 Septendecillion Nonillion Nonillion
1057 Octodecillion Nonilliard Thousand nonillion
1060 Novemdecillion Decillion Decillion
1063 Vigintillion Decilliard Thousand decillion
1066 Unvigintillion Undecillion Undecillion
1069 Duovigintillion Undecilliard Thousand undecillion
1072 Trevigintillion Duodecillion Duodecillion
1075 Quattuorvigintillion Duodecilliard Thousand duodecillion
1078 Quinvigintillion Tredecillion Tredecillion
1081 Sexvigintillion Tredecilliard Thousand tredecillion
1084 Septenvigintillion Quattuordecillion Quattuordecillion
1087 Octovigintillion Quattuordecilliard Thousand quattuordecillion
1090 Novemvigintillion Quindecillion Quindecillion
1093 Trigintillion Quindecilliard Thousand quindecillion
10100 Googol Googol Googol
10123 Quadragintillion Vigintilliard .
10^153 Quinquagintillion
10^183 sexagintillion
10^213 septuagintillion
10^243 octogintillion
10^273 nonagintillion
10303 Centillion Quinquagintilliard
10^603 ducentillion
10^3003 Millinillion
10^3000003 Micrillion
10^3000000003 Nanillion
10^3*10^12+3 Picillion
10^3*10^33+3 Mecillion
10^10^100 Googolplex
10^10^303 Ecetonplex
10^10^3003 Chalatonplex
10^10^10^34 Skewes number
10^10^10^100 Googolplexian
10^10^10^303 Ecetonplexian
3↑↑↑3 Tritri
4↑↑↑↑4 Tritret
10↑↑↑3 Super K
mr furnival

There is also the number googol, which is a 1 with 100 zeros behind it (10,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000), and the number googolplex, which is a 1 with a googol of zeros behind it, (1010,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000) (1010100). And also the number googolplexian, 1 with a googolplex number of zeros behind it. Googolplexianplex, or googolplexianplexian are still theoretical numbers, but they might have some use in real life.

The name centillion was devised in the 19th century for the 100th "illion", being 10303 in short form and 10600 in long form.

million

billion

trillion

quintillion

sextillion

septillion

octillion

nonillion

decillion

undecillion

duodecillion

tredecillion

quattuordecillion

quindecillion

sexdecillion

septendecillion

octodecillion

novemdecillion

vigintillion

unvigintillion

duovigintillion

trevigintillionth

quattuorvigintillion

quinvigintillion

sexvigintillion

septenvigintillion

octovigintillion

novemvigintillion

trigintillion

googol

quinquagintillion

sexagintillion

septuagintillion

octogintillion

nonagintillion

centillion

thɑt's so big

ducentillion

trucentillion

quingentillion

octingentillion

millinillion

dumillinillion

quinmillinillion

decimillinillion / myrillion

centimillinillion

micrillion

nanillion

picillion

femtillion

attillion

zeptillion

yoctillion

xonillion

vecillion

mecillion

duecillion

trecillion

tetrecillion

pentecillion

hexecillion

heptecillion

octecillion

ennecillikon

icosillion

meicosillion

doeicosillion

trioicosillion

tetreicosillion

penteicosillion

hexeicosillion

hepteicosillion

octeicosillion

enneicosillion

triacontillion

googolplex

tetracontillion

pentacontillion

hexacontillion

heptacontillion

octacontillion

ennacontillion

hectillion

killinillion

megillion

gigillion

terillion

petillion

exillion

zettillion

yottillion

xennillion

dakillion

hendillion

dokillion

tedakillion

pedakillion

exdakillion

zedakillion

yodakillion

nedakillion

ikillion

ikenillion

icodillion

ictrillion

icterillion

icpetillion

ikectillion

iczetillion

icyotillion

ixentillion

trakillion

googolduplex / googolplexian

tekillion

pekillion

exakillion

zakillion

yokillion

nekillion

hotillion

botillion

trotillion

totillion

potillion

exotillion

zottillion

yottillion

notillion

kalillion

dalillion

tralillion

talillion

palillion

exalillion

zalillion

yalillion

nalillion

dakalillion

hotalillion

mejillion

gijillion

astillion

lunillion

fermillion

jovillion

solillion

betillion

glocillion

gaxillion

supillion

versillion

multillion

the end