131 (number)

From Wikipedia, the free encyclopedia
← 130 131 132 →
130 131 132 133 134 135 136 137 138 139
List of numbersIntegers
0 100 200 300 400 500 600 700 800 900
Cardinalone hundred thirty-one
Ordinal131st
(one hundred thirty-first)
Factorizationprime
Prime32nd
Divisors1, 131
Greek numeralΡΛΑ´
Roman numeralCXXXI
Binary100000112
Ternary112123
Octal2038
DuodecimalAB12
Hexadecimal8316

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 . 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[]

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 which launched in April 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 748749 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[]


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.
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