Properties of the Number 21809

Twenty-One Thousand Eight Hundred Nine

Basics

Value: 21808 → 21809 → 21810

Parity: odd

Prime: No

Previous Prime: 21803

Next Prime: 21817

Digit Sum: 20

Digital Root: 2

Palindrome: No

Factorization: 113 × 193

Divisors: 1, 113, 193, 21809

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101010100110001

Octal: 52461

Duodecimal: 10755

Hexadecimal: 5531

Square: 475632481

Square Root: 147.6787053031005

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

Fifth diagonal of triangle A064094. A64096

Number of walks within N³ (the first octant of Z³) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 0, 1), (1, -1, -1), (1, 1, -1), (1, 1, 1)}. A149629

Numbers such that the sum of the reverse of their aliquot parts is equal to the reverse of the sum of their aliquot parts. A278948

The sequence denoted by q_n used in the calculation of A323260. A323267

Decimal expansion of 1/805. A21809