Properties of the Number 25681

Twenty-Five Thousand Six Hundred Eighty-One

Basics

Value: 25680 → 25681 → 25682

Parity: odd

Prime: No

Previous Prime: 25679

Next Prime: 25693

Digit Sum: 22

Digital Root: 4

Palindrome: No

Factorization: 61 × 421

Divisors: 1, 61, 421, 25681

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 110010001010001

Octal: 62121

Duodecimal: 12A41

Hexadecimal: 6451

Square: 659513761

Square Root: 160.25292509030842

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

Composite numbers k that divide 3^k - 2^k - 1, excluding powers of 2, 3 and 7. A127073

G.f.: 1/∏_k>=1 (1-prime(k)*x^prime(k)). A2098

Numbers n such that the decimal number concat(6,n) is a square. A273361

Numerators of b(n) = (1/16ⁿ)*(4/(8·n+1) - 2/(8·n+4) - 1/(8·n+5) - 1/(8·n+6)). A48581

Semiprimes in A054567. A113692

a(n) is the numerator of (120·n² + 151·n + 47)/(512·n⁴ + 1024·n³ + 712·n² + 194·n + 15). A374580

a(n) = 16·n² + 2·n + 1. A204675

Strong pseudoprimes to base 29. A20255

Numerators of continued fraction convergents to sqrt(281). A41528

Numbers n such that h(n) = 3 h(n-1) where h(n) is the length of the sequence {n, f(n), f(f(n)), ...., 1} in the Collatz (or 3x + 1) problem. (The earliest "1" is meant.) A78420