Properties of the Number 21812

Twenty-One Thousand Eight Hundred Twelve

Basics

Value: 21811 → 21812 → 21813

Parity: even

Prime: No

Previous Prime: 21803

Next Prime: 21817

Digit Sum: 14

Digital Root: 5

Palindrome: Yes

Factorization: 2 ² × 7 × 19 × 41

Divisors: 1, 2, 4, 7, 14, 19, 28, 38, 41, 76

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101010100110100

Octal: 52464

Duodecimal: 10758

Hexadecimal: 5534

Square: 475763344

Square Root: 147.68886213929608

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

Expansion of ∏_k>=1 (1 - x^k)¹². A735

Base-10 palindromes that start with 2. A43037

Palindromes with exactly 5 prime factors (counted with multiplicity). A46331

a(1) = 0, a(2) = 1; and for n > 2, a(n) = 2·a(A285712(n)) + [1 == (n mod 3)]. A292591

Expansion of f(x)¹² in powers of·where f() is a Ramanujan θ function. A209676

Palindromes which are sums of two consecutive primes. A162571

Even palindromes in which parity of digits alternates. A30149

The number of boundary edges for all ordered trees with n edges. A228178

Palindromes that can be written as the sum of two palindromic primes. A356824

Palindromic even lucky numbers. A45960