Properties of the Number 31991

Thirty-One Thousand Nine Hundred Ninety-One

Basics

Value: 31990 → 31991 → 31992

Parity: odd

Prime: Yes

Previous Prime: 31981

Next Prime: 32003

Digit Sum: 23

Digital Root: 5

Palindrome: No

Factorization: 31991

Divisors: 1, 31991

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 111110011110111

Octal: 76367

Duodecimal: 1661B

Hexadecimal: 7cf7

Square: 1023424081

Square Root: 178.86028066622282

Classification

Fibonacci: No

Bell Number: No

Factorial Number: No

Regular Number: No

Perfect Number: No

Special

Kaprekar Constant: No

Munchausen Constant: No

Armstrong Number: No

Kaprekar Number: No

Catalan Number: No

Vampire Number: No

Taxicab Number: No

Super Prime: No

Friedman Number: No

Fermat Number: No

Cullen Number: No

OEIS Sequences

Number of decagons that can be formed with perimeter n. A288256

Emirps whose internal digits are also an emirp. A225235

Convolution of primes with odd primes. A209403

Primes prime(k) such that prime(k)*k falls between twin primes. A80174

Partial sums of Catalan numbers A000108 multiplied by powers of -7. A113266

a(n) = A001672(n) - A115239(n). A115240

Palindromic primes in base 8 which are also emirps (A006567) in base 10. A168110

Primes p such that (p+18), (p+36) and (p+72) are also prime. A175158

Primes of the form 4·n³-9. A200734

Primes of the form 5n² - 9. A201790