131 (number)

← 130 131 132 →
← 130 131 132 133 134 135 136 137 138 139 → List of numbers — Integers ← 0 100 200 300 400 500 600 700 800 900 →
Cardinal	one hundred thirty-one
Ordinal	131st (one hundred and thirty-first)
Factorization	prime
Prime	32nd
Divisors	1, 131
Roman numeral	CXXXI
Binary	100000112
Ternary	112123
Quaternary	20034
Quinary	10115
Senary	3356
Octal	2038
Duodecimal	AB12
Hexadecimal	8316
Vigesimal	6B20
Base 36	3N36

131 (one hundred [and] thirty-one) is the natural number following 130 and preceding 132.

In mathematics

131 is a Sophie Germain prime,^[1] an irregular prime,^[2] the second 3-digit palindromic prime, and also a permutable prime with 113 and 311. It can be expressed as the sum of three consecutive primes, 131 = 41 + 43 + 47. 131 is an Eisenstein prime with no imaginary part and real part of the form $3n-1$. Because the next odd number, 133, is a semiprime, 131 is a Chen prime. 131 is an Ulam number.^[3]

131 is a full reptend prime in base 10 (and also in base 2). The decimal expansion of 1/131 repeats the digits 007633587786259541984732824427480916030534351145038167938931 297709923664122137404580152671755725190839694656488549618320 6106870229 indefinitely.

In the military

• Convair C-131 Samaritan was an American military transport produced from 1954 to 1956
• USNS Mission Santa Barbara (T-AO-131) was a Buenaventura-class fleet oiler during World War II
• USS Bandera (APA-131) was a is a United States Navy Haskell-class attack transport ship during World War II
• USS Buchanan (DD-131) was a United States Navy Wickes-class destroyer
• USS General T. H. Bliss (AP-131) was a United States Navy General G. O. Squier transport ship during World War II
• USS Hammann (DE-131) was a United States Navy Edsall-class destroyer escort during World War II
• USS Melucta (AK-131) was a United States Navy Crater-class cargo ship during World War II
• USS Walter X. Young (APD-131) was a ship of the United States Navy during World War II
• Strike Fighter Squadron (VFA-131) is a United States Navy F/A-18C Hornet fighter squadron stationed at Naval Air Station Oceana
• ZIL-131 is a 3.5-ton 6x6 army truck

In transportation

• London Buses route 131 is a Transport for London contracted bus route in London
• The Fiat 131 Mirafiori small/medium family car produced from 1974 to 1984
• STS-131 is a NASA Contingency Logistic Flight (CLF) of the Space Shuttle Atlantis planned for no earlier than February 2010

In other fields

131 is also:

• The year AD 131 or 131 BC
• 131 AH is a year in the Islamic calendar that corresponds to 748 – 749 CE.
• 131 Vala is an inner Main belt asteroid
• Iodine-131, or radioiodine, is a radioisotope of iodine for medical and pharmaceutical use
• ACP-131 is the controlling publication for listing of Q codes and Z codes, as published by NATO Allied countries
• Sonnet 131 by William Shakespeare
• 131 is the medical emergency telephone number in Chile
• United States Citizenship and Immigration Services Form I-131 to apply for a travel document, reentry permit, refugee travel document or advance parole
• 131 is the ID3v1 tag equivalent to Indie music

See also

• List of highways numbered 131
• United Nations Security Council Resolution 131

References

1. "Sloane's A005384 : Sophie Germain primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-27.
2. "Sloane's A000928 : Irregular primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-27.
3. "Ulam numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. 2016-04-18. Retrieved 2016-04-19.