Properties of the Number 21022

Twenty-One Thousand Twenty-Two

Basics

Value: 21021 → 21022 → 21023

Parity: even

Prime: No

Previous Prime: 21019

Next Prime: 21023

Digit Sum: 7

Digital Root: 7

Palindrome: No

Factorization: 2 × 23 × 457

Divisors: 1, 2, 23, 46, 457, 914, 10511, 21022

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: Yes

Tetrahedral: No

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Representations

Binary: 101001000011110

Octal: 51036

Duodecimal: 101BA

Hexadecimal: 521e

Square: 441924484

Square Root: 144.98965480336864

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

E.g.f. satisfies: A(x) = ∑_n>=0 xⁿ/n! * A(x)^n(n-1/2). A155804

Numbers which are both heptagonal and centered heptagonal. A128919

Least k such that k*(2^p-1)*(k*(2^p-1)-1)-1 is prime, where 2^p-1 runs through the Mersenne primes. A137906

a(n) = [xⁿ] ∏_k>=1 (1 + x^k)^binomial(k+n-1,n-1). A344098

Positive integers that have exactly ten representations of the form 1 + p1 * (1 + p2* ... * (1 + p_j)...), where [p1, ..., p_j] is a (possibly empty) list of distinct primes. A317400

Centered heptagonal numbers which are sphenic numbers. A360183

Coordination sequence for Cr3Si, Cr position. A9928

Heptagonal numbers for which the sum of the digits is also a heptagonal number. A117650

Heptagonal numbers for which the digital root is also a heptagonal number. A117663

Multiples of 23 whose digit reversal - 1 is also a multiple of 23. A166400