Properties of the Number 21988

Twenty-One Thousand Nine Hundred Eighty-Eight

Basics

Value: 21987 → 21988 → 21989

Parity: even

Prime: No

Previous Prime: 21977

Next Prime: 21991

Digit Sum: 28

Digital Root: 1

Palindrome: No

Factorization: 2 ² × 23 × 239

Divisors: 1, 2, 4, 23, 46, 92, 239, 478, 956, 5497

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010111100100

Octal: 52744

Duodecimal: 10884

Hexadecimal: 55e4

Square: 483472144

Square Root: 148.28351223247984

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

Cluster series for bond percolation problem on square lattice. A3198

Number of polyiamonds with n cells, with holes. A70764

T(n,k)=Number of nXk 0..7 arrays with every nonzero element less than or equal to at least two horizontal and vertical neighbors. A203443

Number of integer compositions of n in which runs of 1's all have length <= 1, runs of 2's all have length <= 2, runs of 3's all have length <= 3, etc. A389510

Number of ways to fill a Young diagram with positive integers summing to n such that all rows and columns are weakly increasing. A323450

Number of nX2 0..7 arrays with every nonzero element less than or equal to at least two horizontal and vertical neighbors. A203437

Numbers n such that n⁹+9 and n⁹-9 are prime. A239505

Number of nX3 0..1 arrays with every element unequal to 0, 1, 2 or 7 king-move adjacent elements, with upper left element zero. A304225

Even composites m such that A003499(m)==6 (mod m). A338311

Number of nX6 0..7 arrays with every nonzero element less than or equal to at least two horizontal and vertical neighbors. A203441