# 127 number

**127** is the natural number following 126 and preceding 128.

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Cardinal | One hundred [and] twenty-seven |

Ordinal | 127th |

Factorization | prime number |

Roman numeral | CXXVII |

Binary | 1111111 |

Hexadecimal | 7F |

## In mathematics

*One hundred [and] twenty-seven* is a Mersenne prime, 2^{7} - 1, and as such, in binary it is a repunit prime, a permutable prime and a palindromic prime. This also means it is the largest integer that can be represented by a signed byte. As a Mersenne prime, 127 is related to the perfect number 8128, and 2^{127} - 1 is also a Mersenne prime, making it a double Mersenne prime. 127 is also a cuban prime of the form , . The next prime is 131, with which it comprises a cousin prime. Because the next odd number, 129, is a semiprime, 127 is a Chen prime.

127 is a centered hexagonal number.

It is the 7th Motzkin number.

It is a nice Friedman number in base 10, since 127 = -1 + 2^{7}, as well as binary since 1111111 = (1 + 1)^{111} - 1 * 1.

## In other fields

**One hundred [and] twenty-seven** is also:

- ASCII and Unicode code point for delete.
- The number of provinces ruled by King Xerxes I, "from India to Ethiopia" (Holy Bible, Esther 1:1).
- The number of sons of Bethlehem at the Census of men of Israel upon return from exile (Holy Bible, Ezra 2:21).
- The year AD
**127**or 127 BC.

es:Ciento veintisiete fr:127 (nombre) ko:127 ja:127 ru:127 (число) sl:127 (število) zh:127