# Names for large numbers

(Redirected from Centillion)

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 x 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 x 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
600 000 000 000 000 000 000 000 000 6 x 1026 600 septillion (quadrillion)
765 476 250 000 000 7.6547625 x 1014 765 trillion, 476 billion, 250 million
145 000 1.45 x 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
101 Ten Ten Ten da Deca-
102 Hundred Hundred Hundred h Hecto-
103 Thousand Thousand Thousand K Kilo-
104 Ten thousand Ten thousand Ten thousand my (Now obsolete) Myria- (Now obsolete)
105 Hundred thousand Hundred thousand Hundred thousand
106 Million Million Million M Mega-
109 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-
1030 Nonillion Quintilion Quintillion
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
1096 Untrigintillion Sexdecillion Sexdecillion
1099 Duotrigintillion Sexdecilliard Thousand sexdecillion
10100 Googol Googol Googol
10102 Tretrigintillion Septendecillion Septendecillion
10105 Quattuortrigintillion Septendecilliard Thousand septedecillion
10108 Quintrigintillion Octodecillion Octodecillion
10111 Sextrigintillion Octodecilliard Thousand octodecillion
10114 Septentrigintillion Novemdecillion Novemdecillion
10117 Octotrigintillion Novemdecilliard Thousand novemdecillion
10120 Novemtrigintillion Vigintillion Vigintillion
10303 Centillion Quinquagintilliard .
1030,003 Myrillion decmillillion decimillillion
10{100,10^100, 2, 2} Googol-Suthrex . .

There is also the number googol, which is a 1 with 100 zeros behind it (10100), and the number googolplex, which is a 1 with a googol of zeros behind it, (10googol) (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.