## Million, Billion, Trillion...

source: http://www.jimloy.com/math/billion.htmPeople 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 |

**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.

## Add a comment