127 (number)
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127 is the natural number following 126 and preceding 128.
| Template:Numbers 120s | |
| Cardinal | One hundred [and] twenty-seven |
| Ordinal | 127th |
| Factorization | prime number |
| Roman numeral | CXXVII |
| Binary | 1111111 |
| Hexadecimal | 7F |
In mathematics
One hundred twenty-seven is a Mersenne prime, 27 - 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 2127 - 1 is also a Mersenne prime, making it a double Mersenne prime. 127 is also a cuban prime of the form <math>p = (x^3 - y^3) / (x - y)<math>, <math>x = y + 1<math>. The next prime is 131, with which it comprises a cousin 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 + 27, as well as binary since 1111111 = (1 + 1)111 - 1 * 1.
In other fields
One hundred 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