Properties of the Number 21916

Twenty-One Thousand Nine Hundred Sixteen

Basics

Value: 21915 → 21916 → 21917

Parity: even

Prime: No

Previous Prime: 21911

Next Prime: 21929

Digit Sum: 19

Digital Root: 1

Palindrome: No

Factorization: 2 ² × 5479

Divisors: 1, 2, 4, 5479, 10958, 21916

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101010110011100

Octal: 52634

Duodecimal: 10824

Hexadecimal: 559c

Square: 480311056

Square Root: 148.04053498957643

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

Expansion of ∏_m>=1 (1 + q^m)^m; number of partitions of n into distinct parts, where n different parts of size n are available. A26007

a(n) = ∑_k=1..n floor(n/k) * (-2)^k-1. A344817

Expansion of (1/(1 - x)) * ∑_k>=0 x^2·k / ∏_j=1..2·k (1 - x^j). A304620

G.f.: exp( ∑_n>=1 binomial(2·n,n)² * xⁿ/n ). A224734

Let Do(n)=A006566(n)=n-th dodecahedral number. Consider all integer triples (i,j,k), j >= k>0, with Do(i)=Do(j)+Do(k), ordered by increasing i; sequence gives j values. A53018

Coefficient of·in the reduction by x² -> x+1 of the polynomial p(n,x) defined at Comments. A192972

Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 94 ones. A31862

a(n) = a(n-1) + 3·a(n-2) -2·a(n-3) - 2·a(n-4), where a(0) = 0, a(1) = -1, a(2) = 1, a(3) = 1. A295726

a(n) = a(n-1) + 3·a(n-2) -2·a(n-3) - 2·a(n-4), where a(0) = -1, a(1) = -1, a(2) = -1, a(3) = 1. A295732

O.g.f. A(x) satisfies: [xⁿ] exp( n² * x·A(x) ) * (n + 1 - A(x)) = 0 for n >= 0, where A(0) = 1. A305116