Properties of the Number 7981

Seven Thousand Nine Hundred Eighty-One

Basics

Value: 7980 → 7981 → 7982

Parity: odd

Prime: No

Previous Prime: 7963

Next Prime: 7993

Digit Sum: 25

Digital Root: 7

Palindrome: No

Factorization: 23 × 347

Divisors: 1, 23, 347, 7981

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

8509 Try Today's Challenge

Representations

Binary: 1111100101101

Octal: 17455

Duodecimal: 4751

Hexadecimal: 1f2d

Square: 63696361

Square Root: 89.3364427319557

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 integer compositions of n whose leaders of weakly decreasing runs are distinct. A374743

Values of n such that L(20) and N(20) are both prime, where L(k) = (n²+n+1)*2^2·k + (2·n+1)*2^k + 1, N(k) = (n²+n+1)*2^k + n. A227523

Numbers m > 1 such that a record number of numbers k have m as the sum of the proper divisors of k. A238895

Numbers k such that the square of k is the concatenation of two numbers m and m-8. A115446

a(1) = 1; a(n) = max{ 5·a(k) + a(n-k) | 1 <= k <= n/2 } for n > 1. A130667

Concentric 19-gonal numbers. A195048

Concentric 21-gonal numbers. A195049

a(n) = n³ - n + 1. A61600

a(n) = 5·n² + 20·n + 1. A162316

Nested floor product of n and fractions (k+1)/k for all k>0 (mod 3), divided by 3. A73360