Properties of the Number 21920

Twenty-One Thousand Nine Hundred Twenty

Basics

Value: 21919 → 21920 → 21921

Parity: even

Prime: No

Previous Prime: 21911

Next Prime: 21929

Digit Sum: 14

Digital Root: 5

Palindrome: No

Factorization: 2 ⁵ × 5 × 137

Divisors: 1, 2, 4, 5, 8, 10, 16, 20, 32, 40

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101010110100000

Octal: 52640

Duodecimal: 10828

Hexadecimal: 55a0

Square: 480486400

Square Root: 148.05404418657398

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

Smallest k > 0 with gcd(k, rev(k)) = n, where rev(k) is digit reversal of k, or 0 if no such k exists. A69554

Smallest solution to gcd(x, Rev(x)) = 2ⁿ. A71686

Numbers that have exactly seven prime factors counted with multiplicity (A046308) whose digit reversal is different and also has 7 prime factors (with multiplicity). A109027

Triangle read by rows: Number of (2n+1)-step self-avoiding walks on diamond lattice ending at point with x = 2k+1. A227716

Numbers m such that the GCD of the x's that satisfy σ(x) = m is 3. A241648

Eighth column of triangle A055249. A55251

Row 3 of array in A047666. A47667

Number of nonprimes <= prime(n)². A53683

Row sums of correlation triangle for (1+x)³/(1-x). A115293

Expansion of (1+3·x+2·x²) / (1-6·x²-4·x³+2·x⁴). A384635