Properties of the Number 21664

Twenty-One Thousand Six Hundred Sixty-Four

Basics

Value: 21663 → 21664 → 21665

Parity: even

Prime: No

Previous Prime: 21661

Next Prime: 21673

Digit Sum: 19

Digital Root: 1

Palindrome: No

Factorization: 2 ⁵ × 677

Divisors: 1, 2, 4, 8, 16, 32, 677, 1354, 2708, 5416

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010010100000

Octal: 52240

Duodecimal: 10654

Hexadecimal: 54a0

Square: 469328896

Square Root: 147.18695594379278

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

Starts of runs of 3 consecutive tribonacci-Niven numbers (A352089). A352091

Triangle read by rows: T(n,k) = t(n-k, k); t(n,m) = f(m)*t(n-1,m) + f(n)*t(n,m-1), where f(x) = 6·x + 2. A257616

Array read by antidiagonals: T(n,k) = number of n-step knight's tours on a (k+2)X(k+2) board summed over all starting positions. A186851

At stage 1, start with a unit equilateral triangle. At each successive stage add 3*(n-1) new triangles around outside with vertex-to-vertex contacts. Sequence gives number of triangles at n-th stage. A269064

Numbers n with property that for each single digit d of n, we can also see the decimal expansion of 2^d as a substring of n. Also n may not contain any zero digits. A135016

Number of 7-step knight's tours on an (n+2) X (n+2) board summed over all starting positions. A186856

Coordination sequence for α-Mn, Position Mn4. A9953

Coordination sequence for σ-CrFe, Position Xb. A9960

Numbers incremented by their digit product produce a cube. A229185

Number of (n+1) X (5+1) 0..1 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing x(i,j)-x(i-1,j) in the j direction. A250608