http://www.jimloy.com/math/billion.htm © Copyright 1999, Jim Loy (Some alterations) People sometimes ask me the names of the large numbers. Here is a table. The system used in the U.S. is not as logical as that used in other countries (like Great Britain, France, and Germany). In these other countries, a billion (bi meaning two) has twice as many zeros as a million, and a trillion (tri meaning three) has three times as many zeros as a million, etc. But the scientific community seems to use the American system. Exponential Number of zeros U.S. & scientific community Other countries Notation 3 x 103 thousand thousand 6 x 106 million million 9 x 109 billion 1000 million (1 milliard) 12 x 1012 trillion billion 15 x 1015 quadrillion 1000 billion 18 x 1018 quintillion trillion 21 x 1021 sextillion 1000 trillion 24 x 1024 septillion quadrillion 27 x 1027 octillion 1000 quadrillion 30 x 1030 nonillion quintillion 33 x 1033 decillion 1000 quintillion 36 x 1036 undecillion sextillion 39 x 1039 duodecillion 1000 sextillion 42 x 1042 tredecillion septillion 45 x 1045 quattuordecillion 1000 septillion 48 x 1048 quindecillion octillion 51 x 1051 sexdecillion 1000 octillion 54 x 1054 septendecillion nonillion 57 x 1057 octodecillion 1000 nonillion 60 x 1060 novemdecillion decillion 63 x 1063 vigintillion 1000 decillion 66 - 120 undecillion - vigintillion 303 x 10303 centillion 600 x 10600 centillion Addendum: There are other big numbers with names. A zillion has come to mean an arbitrary or unknown large number. A googol is 10^100. A googolplex is 10^googol (10^10^10^2). This number is too large to write here without exponents. Skewes' number (gesundheit) is 10^10^10^34 was used as an upper bound in a mathematical proof. Recently 10^10^10^10^10^7 was used in a proof. The googolplex has given rise to the n-plex notation: n-plex is 10^n. n-minex is 10^-n. Donald Knuth invented arrow notation, where m^n (^ is an up arrow) is the regular m^n. m^^n is m^m^m^m...^m, with n up arrows. m^^^n is m^^m^^m...^^m, with n ^^s. According to The Book of Numbers by J.H.Conway and R.K.Guy, chained arrow notation is the following enhancement: a^^^^^b is written as a>b>5, where > is a right arrow. .