Properties of the Number 21667

Twenty-One Thousand Six Hundred Sixty-Seven

Basics

Value: 21666 → 21667 → 21668

Parity: odd

Prime: No

Previous Prime: 21661

Next Prime: 21673

Digit Sum: 22

Digital Root: 4

Palindrome: No

Factorization: 47 × 461

Divisors: 1, 47, 461, 21667

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101010010100011

Octal: 52243

Duodecimal: 10657

Hexadecimal: 54a3

Square: 469458889

Square Root: 147.1971467114767

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) = (2·n-1)*(5·n²-5·n+6)/6. A63489

Nonprimes k such that k divides 3^k-1 - 2^k-1. A73631

G.f.: ∑_k>=0 x^k * ∏_j=1..3·k (1 + x^j)/(1 - x^j). A385089

Index sequence for limit-block extending A000002 (Kolakoski sequence) with first term as initial block. A246145

Numbers k such that 10⁹⁹⁹ + k is a (titanic) prime. A74282

Pseudoprimes to base 21. A20149

Strong pseudoprimes to base 14. A20240

Strong pseudoprimes to base 20. A20246

Strong pseudoprimes to base 22. A20248

Strong pseudoprimes to base 41. A20267