Properties of the Number 21216

Twenty-One Thousand Two Hundred Sixteen

Basics

Value: 21215 → 21216 → 21217

Parity: even

Prime: No

Previous Prime: 21211

Next Prime: 21221

Digit Sum: 12

Digital Root: 3

Palindrome: No

Factorization: 2 ⁵ × 3 × 13 × 17

Divisors: 1, 2, 3, 4, 6, 8, 12, 13, 16, 17

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101001011100000

Octal: 51340

Duodecimal: 10340

Hexadecimal: 52e0

Square: 450118656

Square Root: 145.657131648265

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

Numbers which are divisible by prime(d) for all digits d in their decimal representation. A256786

Rectangular array of coefficients in successive iterations of x·exp(x), as read by antidiagonals. A174480

Record (maximal) gaps between prime triples (p, p+2, p+6). A201598

Number of polyhexes with n cells that tile the plane by 180-degree rotation (Conway criterion). A75211

Nonnegative values·of solutions (x, y) to the Diophantine equation x² + (x+289)² = y². A207059

A convolution triangle of numbers obtained from A034255. A48882

Coefficients of power series that satisfies A(x)⁴ - 16x·A(x)⁵ = 1, A(0)=1. A78533

Numbers of the form p⁵*q·r*s where p, q, r, and s are distinct primes. A179704

Related to quartic factorial numbers A007696. A34255

a(n) = coefficient of xⁿ/(n-1)! in the (n+1)-th iteration of x·exp(x) for n>=1. A174483