Properties of the Number 690

Six Hundred Ninety

Basics

Value: 689 → 690 → 691

Parity: even

Prime: No

Previous Prime: 683

Next Prime: 691

Digit Sum: 15

Digital Root: 6

Palindrome: No

Factorization: 2 × 3 × 5 × 23

Divisors: 1, 2, 3, 5, 6, 10, 15, 23, 30, 46

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 1010110010

Octal: 1262

Duodecimal: 496

Hexadecimal: 2b2

Square: 476100

Square Root: 26.267851073127396

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

List of totally balanced sequences of 2n binary digits written in base 10. Binary expansion of each term contains n 0's and n 1's and reading from left to right (the most significant to the least significant bit), the number of 0's never exceeds the number of 1's. A14486

Denominator of Bernoulli number B_n. A27642

a(n) = ∑_k=1..n k·floor(n/k); also ∑_k=1..n σ(k) where σ(n) = sum of divisors of n (A000203). A24916

Denominators of Bernoulli numbers B_2n. A2445

Smith (or joke) numbers: composite numbers k such that sum of digits of k = sum of digits of prime factors of k (counted with multiplicity). A6753

a(1) = 1 and a(n) = ceiling((∑_k=1..n-1 a(k))/3) for n >= 2. A72493

Products of exactly four distinct primes. A46386

Generalized 11-gonal (or hendecagonal) numbers: m*(9·m - 7)/2 with m = 0, 1, -1, 2, -2, 3, -3, ... A195160

Number of unlabeled multiset antichains of weight n. A293993

Numbers k such that k¹⁶ + 1 is prime. A6313