Properties of the Number 31720

Thirty-One Thousand Seven Hundred Twenty

Basics

Value: 31719 → 31720 → 31721

Parity: even

Prime: No

Previous Prime: 31699

Next Prime: 31721

Digit Sum: 13

Digital Root: 4

Palindrome: No

Factorization: 2 ³ × 5 × 13 × 61

Divisors: 1, 2, 4, 5, 8, 10, 13, 20, 26, 40

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 111101111101000

Octal: 75750

Duodecimal: 16434

Hexadecimal: 7be8

Square: 1006158400

Square Root: 178.10109488714548

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

Sum of the largest parts in the partitions of n into 8 parts. A308998

Numbers k such that k+1, k+3, k+7 and k+9 are all primes. A125855

G.f. A(x) satisfies A(x) = 1 + x·A(x)² / (1 - x·A(x)⁵). A364740

G.f. A satisfies -x+(1+x³-x)*A+(x⁴-x²)*A²+(x⁵-x³)*A³-x⁴*A⁴ = 0. A177794

G.f.: ∏_{k >= 0} ((1 + x^2·k+1) / (1 - x^2·k+1))^k. A361008

Number of 6-step S, NW and NE-moving king's tours on an n X n board summed over all starting positions. A187380

Number of n X 6 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 1 1 and 1 1 1 vertically. A208778

Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 89. A31587

Numbers n such that 117·2ⁿ-1 is prime. A50584

Column 0 of triangular matrix T=A101479, in which row n equals row (n-1) of T^n-1 followed by '1'. A101481