Properties of the Number 689

Six Hundred Eighty-Nine

Basics

Value: 688 → 689 → 690

Parity: odd

Prime: No

Previous Prime: 683

Next Prime: 691

Digit Sum: 23

Digital Root: 5

Palindrome: No

Factorization: 13 × 53

Divisors: 1, 13, 53, 689

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 1010110001

Octal: 1261

Duodecimal: 495

Hexadecimal: 2b1

Square: 474721

Square Root: 26.248809496813376

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

Triangle T(n,k) read by rows: T(n,k) is the number of compositions of n with k descents, n>=0, 0<=k<=n. A238343

Brilliant numbers: semiprimes (products of two primes, A001358) whose prime factors have the same number of decimal digits. A78972

a(n) = n*(4·n+1). A7742

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

Sums of three consecutive primes. A34961

Numbers whose binary expansion is a decimal prime. A36952

Expansion of g.f. x*(1 + 3·x)/((1 + x)*(1 - x)³). A35608

Numbers k such that 2^k - 3 is prime. A50414

Numbers that are the sum of 5 positive 4th powers. A3339

Even triangular numbers halved. A74378