Properties of the Number 21206

Twenty-One Thousand Two Hundred Six

Basics

Value: 21205 → 21206 → 21207

Parity: even

Prime: No

Previous Prime: 21193

Next Prime: 21211

Digit Sum: 11

Digital Root: 2

Palindrome: No

Factorization: 2 × 23 × 461

Divisors: 1, 2, 23, 46, 461, 922, 10603, 21206

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101001011010110

Octal: 51326

Duodecimal: 10332

Hexadecimal: 52d6

Square: 449694436

Square Root: 145.62280041257276

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

a(n) = floor(C(n+8,8)/C(n+2,2)). A84631

Numbers n such that Fibonacci(n) is not squarefree, but for all proper divisors k of n, Fibonacci(k) is squarefree. A65069

Numbers k such that the first 9 decimal digits of the k-th Fibonacci number is 1-9 pandigital. A112516

Monotonic ordering of set S generated by these rules: if·and y are in S then 3xy-x-y is in S, and 2 is in S. A192529

Sum over all partitions λ of n into 3 distinct parts of ∏_i:λ prime(i). A258358

Sum of the second moments of all partitions of n with weights starting from 1. A66187

Number of nX3 0..1 arrays with exactly floor(nX3/2) elements unequal to at least one king-move neighbor, with new values introduced in row major 0..1 order. A222323

Number of nonempty subsets of {1,2,...,n} in which exactly 1/3 of the elements are <= (n-1)/2. A47172

Number of nonempty subsets of {1,2,...,n} in which exactly 1/3 of the elements are <= (n-2)/2. A47183

Number of walks within N³ (the first octant of Z³) starting at (0,0,0) and consisting of n steps taken from {(-1, 0, 0), (-1, 1, 1), (1, -1, 0), (1, 0, 1), (1, 1, -1)}. A149479