127 (number)

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

In mathematics

• 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 still the largest prime ever discovered by hand calculations. 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 , .^[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 9 regular 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

• 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 ship
• 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 mines from minefields

In religion

• 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

• 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 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
• The non-printable "Delete" (DEL) control character in ASCII.

See also

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

References

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