# User:Charles Matthews/1729 (number)

Appearance

1729 | |
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Cardinal | One thousand seven hundred (and) twenty-nine |

Ordinal | One thousand seven hundred (and) twenty-ninth |

Factorization | |

Roman numeral | MDCCXXIX |

Binary | 11011000001 |

Hexadecimal | 6C1 |

**1729** is an integer, most notable for being the Hardy-Ramanujan number (the smallest number expressible as the sum of two cubes in two different ways). It is also the third Carmichael number.

Numbers such as

- 1729 = 1
^{3}+12^{3}= 9^{3}+10^{3}

which can be expressed as the sum of cubes in *n* distinct ways have been dubbed taxicab numbers, written Ta(*n*). 1729 is thus Ta(2).

Another interesting property of the number is that the 1729th decimal place is the beginning of the first occurrence of all ten digits consecutively in the decimal representation of e.