131 (number)

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← 130 131 132 →
Cardinal one hundred thirty-one
Ordinal 131st
(one hundred thirty-first)
Factorization prime
Prime 32nd
Divisors 1, 131
Greek numeral ΡΛΑ´
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[edit]

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[edit]

In transportation[edit]

In other fields[edit]

131 is also:

See also[edit]


References[edit]

  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.