Properties of the Number 21220

Twenty-One Thousand Two Hundred Twenty

Basics

Value: 21219 → 21220 → 21221

Parity: even

Prime: No

Previous Prime: 21211

Next Prime: 21221

Digit Sum: 7

Digital Root: 7

Palindrome: No

Factorization: 2 ² × 5 × 1061

Divisors: 1, 2, 4, 5, 10, 20, 1061, 2122, 4244, 5305

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

4823 Try Today's Challenge

Representations

Binary: 101001011100100

Octal: 51344

Duodecimal: 10344

Hexadecimal: 52e4

Square: 450288400

Square Root: 145.67086187704115

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

n written in fractional base 3/2. A24629

Numbers that are the sum of 5 positive 9th powers. A3394

Sum of 10 nonzero 8th powers. A3388

G.f. A(x) satisfies A(x)³ = A(x³) + 3·x. A107092

Expansion of ∏_m>=1 (1+q^m)^-5. A22600

Number of partitions of n such that (number parts having multiplicity 1) is not a part and (number of 1s) is not a part. A241509

G.f. A(x) satisfies: (1 - x·A(x))³ = 1 - 3·x - x³*A(x³). A352702

Numerators of continued fraction convergents to sqrt(524). A42002

Exponential transform of the ninth powers A001017. A279642

a(n) = 2·a(n-1) - a(n-4) for n >= 4, where a(0) = 2, a(1) = 4, a(2) = 6, a(3) = 10, a(4) = 16. A288599