Properties of the Number 21380

Twenty-One Thousand Three Hundred Eighty

Basics

Value: 21379 → 21380 → 21381

Parity: even

Prime: No

Previous Prime: 21379

Next Prime: 21383

Digit Sum: 14

Digital Root: 5

Palindrome: No

Factorization: 2 ² × 5 × 1069

Divisors: 1, 2, 4, 5, 10, 20, 1069, 2138, 4276, 5345

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101001110000100

Octal: 51604

Duodecimal: 10458

Hexadecimal: 5384

Square: 457104400

Square Root: 146.21901381147393

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)=Number of (n+1)X(k+1) 0..2 arrays with the permanents of all 2X2 subblocks equal and nonzero. A204840

T(n,k)=Number of ways to reciprocally link elements of an nXk array either to themselves or to exactly two horizontal, vertical and antidiagonal neighbors, without consecutive collinear links. A220681

Array read by antidiagonals: A(n,k) is the number of sets of nonempty subsets of a k-element set where each element appears in at most n subsets. A330964

Array read by antidiagonals: T(n,k) is the number of homeomorphically irreducible leaf colored trees with n leaves of k colors. A339779

Minimal number of moves for the cyclic variant of Hanoi's tower for 4 pegs and n disks, with the final peg one step away. A338024

Number of homeomorphically irreducible leaf colored trees with n leaves of 4 colors. A339784

Number of (n+1)X3 0..2 arrays with the permanents of all 2X2 subblocks equal and nonzero. A204834

Number of (n+1)X6 0..2 arrays with the permanents of all 2X2 subblocks equal and nonzero. A204837

Number of ways to reciprocally link elements of an nX4 array either to themselves or to exactly two horizontal, vertical and antidiagonal neighbors, without consecutive collinear links. A220677

Number of ways to reciprocally link elements of an nX5 array either to themselves or to exactly two horizontal, vertical and antidiagonal neighbors, without consecutive collinear links. A220678