Properties of the Number 631

Six Hundred Thirty-One

Basics

Value: 630 → 631 → 632

Parity: odd

Prime: Yes

Previous Prime: 619

Next Prime: 641

Digit Sum: 10

Digital Root: 1

Palindrome: No

Factorization: 631

Divisors: 1, 631

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 1001110111

Octal: 1167

Duodecimal: 447

Hexadecimal: 277

Square: 398161

Square Root: 25.11971337416094

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

Central polygonal numbers (the Lazy Caterer's sequence): n(n+1)/2 + 1; or, maximal number of pieces formed when slicing a pancake with n cuts. A124

Hex (or centered hexagonal) numbers: 3·n*(n+1)+1 (crystal ball sequence for hexagonal lattice). A3215

Number of necklaces of sets of beads containing a total of n beads. A8965

Centered triangular numbers: a(n) = 3·n*(n-1)/2 + 1. A5448

Primes of the form 10·n+1. A30430

Primes whose binary representation is also the decimal representation of a prime. A65720

Primes of the form 8n+7, that is, primes congruent to -1 mod 8. A7522

Numbers n such that (19ⁿ - 2ⁿ)/17 is prime. A229542

Numbers k such that (27^k - 2^k)/25 is prime. A377031

Irregular primes: primes p such that at least one of the numerators of the Bernoulli numbers B₂, B₄, ..., B_p-3 (A000367) is divisible by p. A928