Properties of the Number 21287

Twenty-One Thousand Two Hundred Eighty-Seven

Basics

Value: 21286 → 21287 → 21288

Parity: odd

Prime: No

Previous Prime: 21283

Next Prime: 21313

Digit Sum: 20

Digital Root: 2

Palindrome: No

Factorization: 7 × 3041

Divisors: 1, 7, 3041, 21287

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101001100100111

Octal: 51447

Duodecimal: 1039B

Hexadecimal: 5327

Square: 453136369

Square Root: 145.90065112945865

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

Number of bracelets (turnover necklaces) of n beads of 2 colors, 7 of them black. A32280

Numbers k such that binomial(4k, k) - 1 is prime. A125240

T(5,n) with T(n,m) as in A063394. A63398

Consecutive states of the linear congruential pseudo-random number generator 171·s mod 30269 when started at s=1. A385031

Denominators of continued fraction convergents to sqrt(31). A41051

Denominators of continued fraction convergents to sqrt(124). A41225

Denominators of continued fraction convergents to sqrt(279). A41525

Number of n X 2 arrays of the minimum value of corresponding elements and their horizontal, vertical, diagonal or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and columns, 0..2 n X 2 array. A219211

The y member of the positive proper fundamental solution (x = x2(n), y = y2(n)) of the second class for the Pell equation x² - D(n)*y² = +8 for even D(n) = A264354(n). A264439

Number of natural numbers between exponents of successive Mersenne primes. A157891