Properties of the Number 21971

Twenty-One Thousand Nine Hundred Seventy-One

Basics

Value: 21970 → 21971 → 21972

Parity: odd

Prime: No

Previous Prime: 21961

Next Prime: 21977

Digit Sum: 20

Digital Root: 2

Palindrome: No

Factorization: 127 × 173

Divisors: 1, 127, 173, 21971

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010111010011

Octal: 52723

Duodecimal: 1086B

Hexadecimal: 55d3

Square: 482724841

Square Root: 148.22617852457776

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 nonequivalent dissections of an (n+2)-gon by nonintersecting diagonals up to rotation and reflection. A1004

Number of partitions of n where the difference between consecutive parts is at most 3. A238863

Counterbalanced numbers: Composite numbers k such that φ(k)/(σ(k)-k) is an integer. A55940

Numbers k such that k divides the sum of digits in factorial base of all numbers from 1 to k. A333702

a(n) = n³ plus sum of digits of n³. A123135

Number of weakly unimodal compositions of n in which the greatest part occurs exactly five times. A320316

Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 23 ones. A31791

a(n) = (a(n-1) + a(n-4))/gcd(a(n-1), a(n-4)) with a(1) = a(2) = a(3) = a(4) = 1. A214652

Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 601", based on the 5-celled von Neumann neighborhood. A272824

Number of entries in the tenth cycles of all permutations of [n]. A285238