127 (number)

	← 120 121 122 123 124 125 126 127 128 129 → List of numbers — Integers ← 0 100 200 300 400 500 600 700 800 900 →
Cardinal	one hundred twenty-seven
Ordinal	127th; (one hundred twenty-seventh)
Factorization	prime
Prime	31st
Divisors	1, 127
Greek numeral	ΡΚΖ´
Roman numeral	CXXVII
Binary	11111112
Ternary	112013
Quaternary	13334
Quinary	10025
Senary	3316
Octal	1778
Duodecimal	A712
Hexadecimal	7F16
Vigesimal	6720
Base 36	3J36

127 (one hundred [and] twenty-seven) is the natural number following 126 and preceding 128. It is also a prime number.

In mathematics[edit]

As a Mersenne prime, 127 is related to the perfect number 8128. 127 is also an exponent for another Mersenne prime 2¹²⁷ - 1, which was discovered by Édouard Lucas in 1876, and held the record for the largest known prime for 75 years - it is the largest prime ever discovered by hand calculations, as well as the largest known double Mersenne prime. Furthermore, 127 is equal to 2⁷ - 1, and 7 is equal to 2³ - 1, and 3 is the smallest Mersenne prime, this makes 7 the smallest double Mersenne prime and 127 the smallest triple Mersenne prime.
127 is also a cuban prime of the form $p=(x^{3}-y^{3})/(x-y)$ , $x=y+1$ .^[1] 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 greater than the arithmetic mean of its two neighboring primes, thus it is a strong prime.^[2]
127 is a centered hexagonal number.^[3]
It is the 7th Motzkin number.^[4]
127 is a palindromic prime in nonary and binary.
It is the first nice Friedman number in base 10, since 127 = -1 + 2⁷, as well as binary since 1111111 = (1 + 1)¹¹¹ - 1 * 1.
127 is the sum of the sums of the divisors of the first 12 positive integers.^[5]
127 is the smallest prime that can be written as the sum of the first two or more odd primes: 127 = 3 + 5 + 7 + 11 + 13 + 17 + 19 + 23 + 29.^[6]
127 is the smallest odd number that can't be written in the form p + 2^x for p=prime number and x=integer, since 127 - 2⁰ = 126, 127 - 2¹ = 125, 127 - 2² = 123, 127 - 2³ = 119, 127 - 2⁴ = 111, 127 - 2⁵ = 95, and 127 - 2⁶ = 63 are all composite numbers.^[7]
127 is an isolated prime where both p-2 and p+2 isn't prime.

In the military[edit]

USNS Mission San Luis Obispo (T-AO-127) was a Mission Buenaventura-class fleet oilers during World War II
USS Admiral W. S. Sims (AP-127) was a United States Navy transport ship
USS Allendale (APA-127) was a United States Navy Haskell-class attack transport
USS Alnitah (AK-127) was a United States Navy Crater-class cargo ship in World War II
USS Raccoon (IX-127) was a United States Navy Armadillo-class tanker
USS Tumult (AM-127) was a United States Navy Auk-class minesweeper for removing naval mines

In religion[edit]

The biblical figure Sarah died at the age of 127.^[8]
According to the Book of Esther 1:1, the Persian Empire under Ahasuerus contained 127 provinces

In transportation[edit]

The small Fiat 127 automobile
London Buses route 127 is a Transport for London contracted bus route in London
127 is the number of many roads, including U.S. Route 127
STS-127 was a Space Shuttle Endeavour mission to the International Space Station which launched on June 15, 2009

In other fields[edit]

127 is also:

127 Hours is a film released in 2010
The year AD 127 or 127 BC
127 AH is a year in the Islamic calendar that corresponds to 744 – 745 CE
127 Johanna, a Main belt asteroid
127 film, a film format
The atomic number of Unbiseptium, an element that has not yet been discovered
The LZ 127 Graf Zeppelin, a dirigible
Sonnet 127 by William Shakespeare
127th Street Ensemble was a troupe of African-American actors which included Tupac Amaru Shakur
In IP (Internet Protocol) Version 4, it is the last Class A network and is also the subnet used for loopback functionality in computer networking
The highest signed 8-bit integer, using two's complement
The non-printable "Delete" (DEL) control character in ASCII.