Properties of the Number 21818

Twenty-One Thousand Eight Hundred Eighteen

Basics

Value: 21817 → 21818 → 21819

Parity: even

Prime: No

Previous Prime: 21817

Next Prime: 21821

Digit Sum: 20

Digital Root: 2

Palindrome: No

Factorization: 2 × 10909

Divisors: 1, 2, 10909, 21818

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010100111010

Octal: 52472

Duodecimal: 10762

Hexadecimal: 553a

Square: 476025124

Square Root: 147.70917371646217

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

Number of integer partitions of n whose product is divisible by the sum of primes of their parts. A330954

Number of compositions of n matching the pattern (2,1,2). A335472

Period of the continued fraction for sqrt(3²ⁿ⁺¹). A64932

Indices of records in A360519. A361108

Boyd's Pisot-like sequence F(0,5,11). A274946

Number of nX3 0..1 arrays with every element equal to 2 or 3 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero. A300367

Intersection of A003052 and A283002. A283003

Square the entries of Pascal's triangle. A8459

Number of (n+1)X(2+1) 0..5 arrays with every 2X2 subblock having the sum of the absolute values of the edge differences equal to 10. A233750

Decimal expansion of 1/814. A21818