Properties of the Number 21929

Twenty-One Thousand Nine Hundred Twenty-Nine

Basics

Value: 21928 → 21929 → 21930

Parity: odd

Prime: Yes

Previous Prime: 21911

Next Prime: 21937

Digit Sum: 23

Digital Root: 5

Palindrome: No

Factorization: 21929

Divisors: 1, 21929

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101010110101001

Octal: 52651

Duodecimal: 10835

Hexadecimal: 55a9

Square: 480881041

Square Root: 148.08443537387717

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

Father primes of order 8. A136077

a(n) = number of steps to reach 0 when starting from k = n³ and repeatedly applying the map that replaces k with k - A055401(k), where A055401(k) = the number of positive cubes needed to sum to k using the greedy algorithm. A261227

Primes p such that A001177(p) = (p-1)/8. A308801

Prime time primes (of the form HMMSS with primes H < 24 and MM, SS < 60) such that the corresponding number of seconds after midnight is also prime. A295000

Primes p such that 8p +1 and (p-1)/8 are primes. A85958

a(n) = (1/2+1/2·i*sqrt(11))ⁿ + (1/2-1/2·i*sqrt(11))ⁿ, where i=sqrt(-1). A131040

Numbers k such that k + sum_of_digits(k) is a cube. A84661

Primes of the form 16·m² + 25 for m=1,2,3,... A87857

a(n) = min{ m : ∑_{n <= i <= m} 1/p_i > 1}, where p_i is the i-th prime = A000040(i). A92325