Properties of the Number 21904

Twenty-One Thousand Nine Hundred Four

Basics

Value: 21903 → 21904 → 21905

Parity: even

Prime: No

Previous Prime: 21893

Next Prime: 21911

Digit Sum: 16

Digital Root: 7

Palindrome: No

Factorization: 2 ⁴ × 37 ²

Divisors: 1, 2, 4, 8, 16, 37, 74, 148, 296, 592

Polygonal

Triangular: No

Square: Yes

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101010110010000

Octal: 52620

Duodecimal: 10814

Hexadecimal: 5590

Square: 479785216

Square Root: 148

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

a(n) = (4·n)². A16802

Largest square <= n³. A65733

Number of 2 X n 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 1 0 1 vertically. A207025

a(n) = (11·n + 5)². A17450

Numbers with prime factorization p²*q⁴. A189988

a(n) = (6·n + 4)². A16958

T(n,k)=Number of nXk 0..2 arrays with rows, diagonals and antidiagonals unimodal. A223789

T(n,k)=Number of nXk 0..2 arrays with rows and antidiagonals unimodal. A223975

a(n) = (7·n + 1)². A16994

Denominator of 1/16 - 1/n². A61042