Properties of the Number 21217

Twenty-One Thousand Two Hundred Seventeen

Basics

Value: 21216 → 21217 → 21218

Parity: odd

Prime: No

Previous Prime: 21211

Next Prime: 21221

Digit Sum: 13

Digital Root: 4

Palindrome: No

Factorization: 7 ² × 433

Divisors: 1, 7, 49, 433, 3031, 21217

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101001011100001

Octal: 51341

Duodecimal: 10341

Hexadecimal: 52e1

Square: 450161089

Square Root: 145.6605643267937

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

T(n,k)=Hilltop maps: number of nXk binary arrays indicating the locations of corresponding elements not exceeded by any horizontal or antidiagonal neighbor in a random 0..1 nXk array. A221446

Molien series for invariants of finite Coxeter group A₁₂. A266781

Composite numbers for which A324644(n)/A324198(n) = 2 and σ(n) == 2 (mod 4). A371082

Square array A(n,k), n>=0, k>=0, read by antidiagonals downwards, where column k is the expansion of 1/(1 - k·x) * ∏_j=0..k-1 (1 + j·x)/(1 - j·x). A383818

First differences of A037260. A37261

Third row of Pascal-(1,7,1) array A081582. A81593

a(n) = 128·n² + 2528·n + 12481. A157436

Numerators of continued fraction convergents to sqrt(663). A42274

Column 3 of triangle A055898. A55899

Shallow diagonal of triangular spiral in A051682. A81275