Properties of the Number 21200

Twenty-One Thousand Two Hundred

Basics

Value: 21199 → 21200 → 21201

Parity: even

Prime: No

Previous Prime: 21193

Next Prime: 21211

Digit Sum: 5

Digital Root: 5

Palindrome: No

Factorization: 2 ⁴ × 5 ² × 53

Divisors: 1, 2, 4, 5, 8, 10, 16, 20, 25, 40

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101001011010000

Octal: 51320

Duodecimal: 10328

Hexadecimal: 52d0

Square: 449440000

Square Root: 145.60219778561037

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

n written in fractional base 3/2. A24629

Autobiographical numbers (or curious numbers): list of numbers m = x₀ x₁ x₂ ... x_b-1 (written in base b) such that x_i is the number of "digits" in m that are equal to i, for all i=0,...,b-1. A46043

a(n) = prime(n)² - prime(n²). Commutator of (primes, squares) at n. A123914

Autobiographical numbers: the first digit specifies how many 0's in the number, the next digit specifies how many 1's, etc. This version is not limited to 10 digits. A138480

Non-palindromic numbers n such that n·reverse(n) is a square and n and reverse(n) do not have the same number of digits. A322835

Number of permutations p of [n] such that 0p has a nonincreasing down-jump sequence. A288912

Square array A(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where column k is the expansion of B(x)^k, where B(x) is the g.f. of A381572. A381571

G.f. A(x) satisfies A(x) = 1/(1 - x·A(x·A(x)))². A381572

Numbers k such that the powerful part of the sum of divisors of k (A387726) is greater than or equal to k, and σ(k) is not itself a powerful number. A387729

In the list of divisors of n (in base 3), each digit 0-2 appears equally often. A45811