Properties of the Number 21257

Twenty-One Thousand Two Hundred Fifty-Seven

Basics

Value: 21256 → 21257 → 21258

Parity: odd

Prime: No

Previous Prime: 21247

Next Prime: 21269

Digit Sum: 17

Digital Root: 8

Palindrome: No

Factorization: 29 × 733

Divisors: 1, 29, 733, 21257

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101001100001001

Octal: 51411

Duodecimal: 10375

Hexadecimal: 5309

Square: 451860049

Square Root: 145.79780519610026

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

n³+Largest square, (Largest square <= n³). A176580

a(n) = (27ⁿ - 2ⁿ)/25. A180844

Odd semiprimes k = p·q such that k = A325820(p,q), with p, q primes > 3, and A325820 is the carryless base-3 multiplication. A391331

Number of special sums of integer partitions of n. A304796

Numbers k of the form (x + y)*(x² + y²) such that (x + y) and (x² + y²) are primes. A349202

Number of compositions (ordered partitions) of n into at most 6 prime parts (counting 1 as a prime). A347761

Positive integers that cannot be written as a sum of a practical number and a heptagonal number. A373444

Number of nX6 0..2 arrays with rows, columns and antidiagonals unimodal and diagonals nondecreasing. A223931

Decimal expansion of 1/253. A21257