Properties of the Number 21213

Twenty-One Thousand Two Hundred Thirteen

Basics

Value: 21212 → 21213 → 21214

Parity: odd

Prime: No

Previous Prime: 21211

Next Prime: 21221

Digit Sum: 9

Digital Root: 9

Palindrome: No

Factorization: 3 ² × 2357

Divisors: 1, 3, 9, 2357, 7071, 21213

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101001011011101

Octal: 51335

Duodecimal: 10339

Hexadecimal: 52dd

Square: 449991369

Square Root: 145.64683312726027

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 partitions of n having no parts equal to the size of their Durfee squares. A118199

Odd composites k such that σ(k) has the same powerful part as k, where σ is the sum of divisors function. A386425

Terms k of A228058 such that gcd(k - A048250(k), A162296(k) - k) = A162296(k) - k. A325376

Triangle of coefficients of polynomials u(n,x) jointly generated with A210865; see the Formula section. A210864

Numbers k in A228058 such that also A001065(k) is in A228058. A325380

Number of ways to partition the set of divisors of the n-th abundant number into three subsets such that their sums form an integer triangle. A91235

a(n) is the smallest number k such that d(1)*1! + d(2)*2! + ... + d(p)*p! = n², where d(i) are the decimal digits of k. A198095

Numbers n such that n | 5ⁿ + 3ⁿ +1. A57829

Squares in lunar arithmetic in base 4 written in base 4. A171460

Number of separations (Carlitz compositions or anti-runs) of the prime indices of n. A335452