Properties of the Number 31861

Thirty-One Thousand Eight Hundred Sixty-One

Basics

Value: 31860 → 31861 → 31862

Parity: odd

Prime: No

Previous Prime: 31859

Next Prime: 31873

Digit Sum: 19

Digital Root: 1

Palindrome: No

Factorization: 151 × 211

Divisors: 1, 151, 211, 31861

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 111110001110101

Octal: 76165

Duodecimal: 16531

Hexadecimal: 7c75

Square: 1015123321

Square Root: 178.4964985650979

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

Numbers n of the form p²-p-1 = A165900(p), for prime p, such that n²-n-1 = A165900(n) is also prime. A237527

a(n) = p² - p - 1 where p = prime(n), the n-th prime. A306190

Strong pseudoprimes to base 19. A20245

Strong pseudoprimes to base 23. A20249

Smallest k>1 such that k(p-1)-1 is divisible by p², p=n-th prime. A39914

Denominators of continued fraction convergents to sqrt(220). A41411

Denominators of continued fraction convergents to sqrt(880). A42701

Expansion of 1/((1-3x)*(1-6x)*(1-10x)). A17952

Squarefree conductors of quintic fields. A85715

p²-p-1 that is not prime, where p is prime. A119609