Properties of the Number 521

Five Hundred Twenty-One

Basics

Value: 520 → 521 → 522

Parity: odd

Prime: Yes

Previous Prime: 509

Next Prime: 523

Digit Sum: 8

Digital Root: 8

Palindrome: No

Factorization: 521

Divisors: 1, 521

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

4823 Try Today's Challenge

Representations

Binary: 1000001001

Octal: 1011

Duodecimal: 375

Hexadecimal: 209

Square: 271441

Square Root: 22.825424421026653

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

Lucas numbers beginning at 2: L(n) = L(n-1) + L(n-2), L(0) = 2, L(1) = 1. A32

Lesser of twin primes. A1359

Mersenne exponents: primes p such that 2^p - 1 is prime. Then 2^p - 1 is called a Mersenne prime. A43

Pythagorean primes: primes of the form 4·k + 1. A2144

Lucas numbers (beginning with 1): L(n) = L(n-1) + L(n-2) with L(1) = 1, L(2) = 3. A204

Twin primes. A1097

Wythoff array read by falling antidiagonals. A35513

Numbers k that divide the (left) concatenation of all numbers <= k written in base 25 (most significant digit on left). A29494

Primes congruent to 1 or 2 modulo 4; or, primes of form x² + y²; or, -1 is a square mod p. A2313

Primes of the form 3n-1. A3627