Properties of the Number 21521

Twenty-One Thousand Five Hundred Twenty-One

Basics

Value: 21520 → 21521 → 21522

Parity: odd

Prime: Yes

Previous Prime: 21517

Next Prime: 21523

Digit Sum: 11

Digital Root: 2

Palindrome: No

Factorization: 21521

Divisors: 1, 21521

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

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Representations

Binary: 101010000010001

Octal: 52021

Duodecimal: 10555

Hexadecimal: 5411

Square: 463153441

Square Root: 146.70037491431302

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 whose base-4 representation also is the base 2-representation of a prime. A235461

Primes which can be expressed as sum of distinct powers of 4. A77718

Primes p whose reciprocal has period (p-1)/10. A56215

Primes having only {1, 2, 5} as digits. A385773

Primes of the form XYX, where Y is a single digit. A154270

Decimal Goedelization of antitheorems from propositional calculus, in Richard C. Schroeppel's metatheory of A101273. A100200

Number of fully chiral set-systems on n vertices. A330282

Define C(n) by the recursion C(0) = 4·i where i² = -1, C(n+1) = 1/(1 + C(n)), then a(n) = 4*(-1)ⁿ/Im(C(n)) where Im(z) denotes the imaginary part of z. A69961

Diagonal of triangle in A082737. A82738

Primes of the form abcabc..abcab. A228627