Return to my Mathematics pages
Go to my home page
© Copyright 1999, Jim Loy
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.
| Number of zeros | U.S. & scientific community | Other countries |
| 3 | thousand | thousand |
| 6 | million | million |
| 9 | billion | 1000 million (1 milliard) |
| 12 | trillion | billion |
| 15 | quadrillion | 1000 billion |
| 18 | quintillion | trillion |
| 21 | sextillion | 1000 trillion |
| 24 | septillion | quadrillion |
| 27 | octillion | 1000 quadrillion |
| 30 | nonillion | quintillion |
| 33 | decillion | 1000 quintillion |
| 36 | undecillion | sextillion |
| 39 | duodecillion | 1000 sextillion |
| 42 | tredecillion | septillion |
| 45 | quattuordecillion | 1000 septillion |
| 48 | quindecillion | octillion |
| 51 | sexdecillion | 1000 octillion |
| 54 | septendecillion | nonillion |
| 57 | octodecillion | 1000 nonillion |
| 60 | novemdecillion | decillion |
| 63 | vigintillion | 1000 decillion |
| 66 - 120 | undecillion - vigintillion | |
| 303 | centillion | |
| 600 | centillion |
See Scientific Notation.
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.