Properties of the Number 31521

Thirty-One Thousand Five Hundred Twenty-One

Basics

Value: 31520 → 31521 → 31522

Parity: odd

Prime: No

Previous Prime: 31517

Next Prime: 31531

Digit Sum: 12

Digital Root: 3

Palindrome: No

Factorization: 3 × 7 × 19 × 79

Divisors: 1, 3, 7, 19, 21, 57, 79, 133, 237, 399

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 111101100100001

Octal: 75441

Duodecimal: 162A9

Hexadecimal: 7b21

Square: 993573441

Square Root: 177.54154443397184

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

a(n) = ∏_{d∣n, d-1 is prime} (d-1)^{1+A286561(n,d-1}), where A286561(n,k) gives the k-valuation of n (for k > 1). A323155

Number of integer partitions of n such that the least and greatest parts are both even or both odd. A391225

Number of distinct primes in the numerator of the 2ⁿ sums generated from the set 1, 1/2, 1/3, ..., 1/n. A75189

Composite squarefree numbers k such that p+1 divides k-1 for any prime p dividing k. A225711

Numbers which are the product of two S-primes (A057948) in exactly three ways. A343828

Odd composite integers m such that U(m)² == 1 (mod m) and V(m) == 7 (mod m), where U(m) and V(m) are the m-th generalized Lucas and Pell-Lucas numbers of parameters a=7 and b=-1, respectively. A337630

Number of balanced ternary words of length n. A260938

a(n) = [xⁿ] (4·x² + x - 1)/(4·x³ + 3·x² + 2·x - 1). A322939

Expansion of (7-14·x+6·x²)/((1-x)*(2·x²-4·x+1)); related to the binomial transform of Pell numbers A000129 (see formula and comment for A007070). A113859

Expansion of -x*(5·x⁴+5·x³-7·x-4)/((x²-x-1)*(x³+x²-1)). A134186