Properties of the Number 21821

Twenty-One Thousand Eight Hundred Twenty-One

Basics

Value: 21820 → 21821 → 21822

Parity: odd

Prime: Yes

Previous Prime: 21817

Next Prime: 21839

Digit Sum: 14

Digital Root: 5

Palindrome: No

Factorization: 21821

Divisors: 1, 21821

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101010100111101

Octal: 52475

Duodecimal: 10765

Hexadecimal: 553d

Square: 476156041

Square Root: 147.7193284577208

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 of the form 2n²+14n+5. A154577

Greatest prime factor of n⁵ + 1. A240548

Column 6 of triangle A117418. A117424

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

Primes having only {1, 2, 8} as digits. A385775

Theorems from propositional calculus, translated into decimal digits. A101273

Primitive prime factors of the cyclotomic polynomial sequence φ(10,k) in the order in which they occur. A248874

Smallest primes of 3 X 3 semimagic squares formed from consecutive primes. A265139

Triangle T, read by rows, formed by a column bisection of triangle A117418: column k of T equals column 2·k of A117418. A117425

Primes of the form abcabc..abcab. A228627