Properties of the Number 21911

Twenty-One Thousand Nine Hundred Eleven

Basics

Value: 21910 → 21911 → 21912

Parity: odd

Prime: Yes

Previous Prime: 21893

Next Prime: 21929

Digit Sum: 14

Digital Root: 5

Palindrome: No

Factorization: 21911

Divisors: 1, 21911

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

4823 Try Today's Challenge

Representations

Binary: 101010110010111

Octal: 52627

Duodecimal: 1081B

Hexadecimal: 5597

Square: 480091921

Square Root: 148.02364675956338

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

Primes having only {1, 2, 9} as digits. A385776

Numbers k such that (12^k + 1)/13 is a prime. A57178

Least prime in A031936 (lesser of 18-twins) whose distance to the next 18-twin is 2·n. A52358

Values of A167053(k)-A167053(k-1)-1 not equal to 1. A167054

Primes p such that the next prime after p can be obtained from p by adding the product of the digits of p. A89823

Base-2 expansion of a(n) encodes the steps where numbers of the form 6k+5 are encountered when map x -> A252463(x) is iterated down to 1, starting from x=n. A292945

a(1) = 0; and for n > 1, a(n) = 2·a(A285712(n)) + [0 == (n mod 3)]. A292590

a(n) is smallest prime > 2·a(n-1), a(1) = 3. A65545

Balanced primes separated from the next lower and next higher prime neighbors by 18. A53073

Primes of the form k² + 7. A79138