Properties of the Number 21391

Twenty-One Thousand Three Hundred Ninety-One

Basics

Value: 21390 → 21391 → 21392

Parity: odd

Prime: Yes

Previous Prime: 21383

Next Prime: 21397

Digit Sum: 16

Digital Root: 7

Palindrome: No

Factorization: 21391

Divisors: 1, 21391

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101001110001111

Octal: 51617

Duodecimal: 10467

Hexadecimal: 538f

Square: 457574881

Square Root: 146.2566237816257

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 compositions of n whose run-lengths cover an initial interval of positive integers. A329766

Balanced primes of order seven. A96699

Initial term in sequence of four consecutive primes whose consecutive differences have d-pattern = [6, 4, 6]; short d-string notation for pattern = [646]. A78856

Primes of the form 2n²+18n+7, n>=0. A154592

Prime number spiral (clockwise, Northwest spoke). A53999

a(n) = prime(n⁴). A109791

Primes in A005891 = Centered pentagonal numbers: (5n² + 5n + 2)/2. A145838

Primes p such that p³ - 12 and p³ + 12 are also primes. A153322

Total sum of Fibonacci parts in all partitions of n. A199936

a(n) = (n³ + 18·n² + 17·n + 6)/6. A143058