Properties of the Number 25805

Twenty-Five Thousand Eight Hundred Five

Basics

Value: 25804 → 25805 → 25806

Parity: odd

Prime: No

Previous Prime: 25801

Next Prime: 25819

Digit Sum: 20

Digital Root: 2

Palindrome: No

Factorization: 5 × 13 × 397

Divisors: 1, 5, 13, 65, 397, 1985, 5161, 25805

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 110010011001101

Octal: 62315

Duodecimal: 12B25

Hexadecimal: 64cd

Square: 665898025

Square Root: 160.63934760823702

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

Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted then there are a pair of central terms both equal to 10. A31423

Numbers m such that 2^m == -1/2 (mod m). A296369

Triangle T, read by rows, where column k of T = column 0 of matrix power T^k+1 for k>0, with column 0 of T = unsigned column 0 of T^-1 (shifted). A152400

Column 1 of triangle A152400; also, column 1 of square array A152405. A152401

Square array, read by antidiagonals, where row n+1 is generated from row n by first removing terms in row n at positions {m*(m+1)/2, m>=0} and then taking partial sums, starting with all 1's in row 0. A152405

Number of free poly-IH10-tiles (holes allowed) with n cells. A197549

{(Product of terms in row n of A082817) + 1} / n. A82821

Positions of those 1's that are followed by a 0, summed over all Fibonacci binary words of length n. A Fibonacci binary word is a binary word having no 00 subword. A152881

Numbers of the form p·q*r where p, q, r are distinct primes congruent to 1 mod 4 such that Legendre(p/q) = Legendre(p/r) = Legendre(q/r) = -1. A323271

Numbers with 3 prime factors a < b < c such that 2c = a⁴ + b². A261657