Naming Large Numbers

NAMING LARGE NUMBERS

To name a large number, first change the number into one which is expressed as N x 10ⁿ, where n is a multiple of 3 and N is between 1 and 999 (starting at the end of the number, use commas to break the number up into groups of three digits). Read N in the normal fashion, followed by the correct word from the list below for the rest of the number. (If the power of 10 is larger than 120, proceed to the bottom of the page.)

Example: 45000000000000000000000000000000000000000000
       = 45,000,000,000,000,000,000,000,000,000,000,000,000,000,000
       = 45 x 10⁴²
       = 45 tredecillion

million		10⁶
billion		10⁹
trillion		10¹²
quadrillion		10¹⁵
quintillion		10¹⁸
sextillion		10²¹
septillion		10²⁴
octillion		10²⁷
nonillion		10³⁰
decillion		10³³
undecillion		10³⁶
dodecillion		10³⁹
tredecillion		10⁴²
quattuordecillion		10⁴⁵
quindecillion		10⁴⁸
sexdecillion		10⁵¹
septendecillion		10⁵⁴
octodecillion		10⁵⁷
novemdecillion		10⁶⁰
vigintillion		10⁶³

unvigintillion		10⁶⁶
dovigintillion		10⁶⁹
trevigintillion		10⁷²
quattuorvigintillion		10⁷⁵
quinvigintillion		10⁷⁸
sexvigintillion		10⁸¹
septenvigintillion		10⁸⁴
octovigintillion		10⁸⁷
novemvigintillion		10⁹⁰
trigintillion		10⁹³
untrigintillion		10⁹⁶
dotrigintillion		10⁹⁹
tretrigintillion		10¹⁰²
quattuortrigintillion		10¹⁰⁵
quintrigintillion		10¹⁰⁸
sextrigintillion		10¹¹¹
septentrigintillion		10¹¹⁴
octotrigintillion		10¹¹⁷
novemtrigintillion		10¹²⁰

RULES FOR NAMING LARGER POWERS OF TENS
(adapted from *The Book of Numbers* by Conway and Guy)
STEP	EXAMPLE
Start with a power of ten that is a multiple of three.	10²⁴⁸⁴
Take that power of 10 and subtract 3.	2484 - 3 = 2481
Divide the result by 3.	2481 / 3 = 827
Starting at the end of the quotient, find each of the prefixes in the table below, ones digit first, tens digit next, etc. (The letters in parentheses are explained in the next step.)	7 = septe (mn) 2 = (ms) viginti 8 = (mx) octingenti
String the segments together, inserting an extra letter if the letter shown in parentheses at the end of one segment matches a letter in parentheses at the beginning of the next.	septemvigintioctingenti (The m was added between septe and viginti because m was in each pair of parentheses.)
If the result ends in a, change the a to i.	septemvigintioctingenti (Rule doesn't apply here.)
Add llion at the end, and you're done!	septemvigintioctingentiillion

PREFIXES
digit	ones digit	tens digit	hundreds digit	thousands digit
0
1	un	(n) deci	(nx) centi	mille
2	duo	(ms) viginti	(n) ducenti
3	tre (s)	(ns) triginta	(ns) trecenti
4	quattuor	(ns) quadraginta	(ns) quadringenti
5	quinqua	(ns) quinquaginta	(ns) quingenti
6	se (sx)	(n) sexaginta	(n) sescenti
7	septe (mn)	(n) septuaginta	(n) septingenti
8	octo	(mx) octoginta	(mx) octingenti
9	nove (mn)	nonaginta	nongenti
NOTE: The above is all based on the American system of naming numbers. The British do it differently. To see a comparsion between the two systems, click HERE.