Properties of the Number 691

Six Hundred Ninety-One

Basics

Value: 690 → 691 → 692

Parity: odd

Prime: Yes

Previous Prime: 683

Next Prime: 701

Digit Sum: 16

Digital Root: 7

Palindrome: No

Factorization: 691

Divisors: 1, 691

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 1010110011

Octal: 1263

Duodecimal: 497

Hexadecimal: 2b3

Square: 477481

Square Root: 26.28687885618983

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

Numerator of Bernoulli number B_n. A27641

Numerators of Bernoulli numbers B_2n. A367

Numerators of the "original" Bernoulli numbers; also the numerators of the Bernoulli polynomials at x=1. A164555

Primes p such that 2p-1 is also prime. A5382

Primes of the form k² + k + 41. A5846

Primes of the form 10·n+1. A30430

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

Positive integers which apparently never result in a palindrome under repeated applications of the function A056964(x) = x + (x with digits reversed). A23108

The Matula-Goebel numbers of the generalized Bethe trees. A generalized Bethe tree is a rooted tree in which vertices at the same level have the same degree. A214577

Primes == 3 (mod 8). A7520