Properties of the Number 21456

Twenty-One Thousand Four Hundred Fifty-Six

Basics

Value: 21455 → 21456 → 21457

Parity: even

Prime: No

Previous Prime: 21433

Next Prime: 21467

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 2 ⁴ × 3 ² × 149

Divisors: 1, 2, 3, 4, 6, 8, 9, 12, 16, 18

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101001111010000

Octal: 51720

Duodecimal: 10500

Hexadecimal: 53d0

Square: 460359936

Square Root: 146.47866738880444

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

The n-th n-gonal number: a(n) = n*(n² - 3·n + 4)/2. A60354

Square table T, read by antidiagonals, where T(n,k) gives the number of n-th generation descendents of a node labeled (k) in the tree of tournament sequences. A93729

T(n,k)=Number of (n+1) X (k+1) 0..2 arrays with the maximum plus the upper median plus the minimum of every 2 X 2 subblock differing from its horizontal and vertical neighbors by exactly one. A237412

Numbers n such that 5·10ⁿ-1 is prime. A56712

θ series of 15-dimensional lattice Kappa₁₅. A362875

Number of degree-n permutations of order dividing 12. A53502

Sums of members of groups in A076062. A76060

Numbers n such that the sum of n consecutive positive cubes is a cube for some initial starting number k. A240970

Expansion of -2·x²*(-3-2·x+x²-x³-2·x⁴+x⁵) / ( (1+x)²*(x-1)⁴ ). A178465

Coefficient of x² in the reduction by (x³ -> x + 1) of the polynomial F(n+1)*xⁿ, where F(n)=A000045 (Fibonacci sequence). A192913