127 (number)

Short description: Natural number

| <- 126  | 127 |  128 ->

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← 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.

## Contents

* 1 In mathematics
* 2 In the military
* 3 In religion
* 4 In transportation
* 5 In other fields
* 6 See also
* 7 References

## In mathematics

* As a Mersenne prime, 127 is related to the perfect number 8128. 127 is also the largest known Mersenne prime exponent for a Mersenne number, 2127−1, which is also a Mersenne prime. It was discovered by Édouard Lucas in 1876 and held the record for the largest known prime for 75 years.
* 2127−1 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, making 7 the smallest double Mersenne prime and 127 the smallest triple Mersenne prime.
* There are a total of 127 prime numbers between 2,000 and 3,000.
* 127 is also a cuban prime of the form p=x3−y3x−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 seventh Motzkin number.[4]
* 127 is a palindromic prime in nonary and binary.
* 127 is the first Friedman prime in decimal. It is also the first nice Friedman number in decimal, since 127=27−1, as well as binary since 1111111=(1+1)111−1 .
* 127 is the sum of the sums of the divisors of the first twelve 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 cannot be written in the form p+2x, for p is a prime number, and x is an 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 neither p−2 nor p+2 is prime.
* 127 is the smallest digitally delicate prime in binary.[8]
* 127 is the 31st prime number and therefore it is the smallest Mersenne prime with a Mersenne prime index.
* 127 is the largest number with the property 127=1⋅prime(1)+2⋅prime(2)+7⋅prime(7), where prime(n) is the nth prime number. There are only two numbers with that property; the other one is 43.
* 127 is equal to prime6(1), where prime(n) is the nth prime number.
* 127 is the number of non-equivalent ways of expressing 10,000 as the sum of two prime numbers[9]
* 127/50 = 2.54, the number of centimeters in one inch.

## In the military

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

## In religion

* The biblical figure Sarah died at the age of 127.[10]
* According to the Book of Esther, the Persian Empire under Ahasuerus consisted of 127 provinces "from India to Ethiopia".[11]
* Havamal Stanza 127 is used as a declaration against folkish traditions of Heathenry and specifically the Asatru Folk Assembly.[12]

## In transportation

* 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

* 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
* NCT 127, K-pop boy group under SM Entertainment
* 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.
* Linotype (and Intertype) machines used brass matrices with one of 127 possible combinations punched into the top to enable the matrices to return to their proper channel in the magazine.
* 127 is the smallest positive integer, n, such that n centimeters is a whole number of inches. 127 cm is exactly 50 inches.
* 127 is the total number of people, including self and all ancestors, in a 7-generation (back to 4-great grandparents) pedigree chart in genealogy.

## See also

* 127th (disambiguation)
* List of highways numbered 127
* United Nations Security Council Resolution 127

## References

1. ↑ "Sloane's A002407 : Cuban primes". OEIS Foundation. https://oeis.org/A002407.
2. ↑ "Sloane's A051634 : Strong primes". OEIS Foundation. https://oeis.org/A051634.
3. ↑ "Sloane's A003215 : Hex (or centered hexagonal) numbers". OEIS Foundation. https://oeis.org/A003215.
4. ↑ "Sloane's A001006 : Motzkin numbers". OEIS Foundation. https://oeis.org/A001006.
5. ↑ Sloane, N. J. A., ed. "Sequence A024916 (sum_{k=1..n} sigma(k) where sigma(n) = sum of divisors of n)". OEIS Foundation. https://oeis.org/A024916.
6. ↑ Sloane, N. J. A., ed. "Sequence A071148". OEIS Foundation. https://oeis.org/A071148. . Partial sums of a sequence of odd primes; a(n) = sum of the first n odd primes.
7. ↑ Sloane, N. J. A., ed. "Sequence A006285 (Odd numbers not of form p + 2^x (de Polignac numbers))". OEIS Foundation. https://oeis.org/A006285.
8. ↑ Sloane, N. J. A., ed. "Sequence A137985". OEIS Foundation. https://oeis.org/A137985. . Complementing any single bit in the binary representation of these primes produces a composite number.
9. ↑ Sloane, N. J. A., ed. "Sequence A065577 (Number of Goldbach partitions of 10^n)". OEIS Foundation. https://oeis.org/A065577. Retrieved 2023-08-31.
10. ↑ "Sara". Catholic Encyclopedia. http://www.newadvent.org/cathen/13468a.htm.
11. ↑ Esther 1:1
12. ↑ "Declaration 127". http://www.declaration127.com/.

* Wells, D. The Penguin Dictionary of Curious and Interesting Numbers London: Penguin Group. (1987): 136 - 138

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