Properties of the Number -685

Six Hundred Eighty-Five

Basics

Value: -686 → -685 → -684

Parity: odd

Prime: No

Previous Prime:

Next Prime: 1

Digit Sum: 19

Digital Root: 1

Palindrome: No

Factorization: 5 × 137

Divisors: 1, 5, 137, 685

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: -1010101101

Octal: -1255

Duodecimal: -491

Hexadecimal: -2ad

Square: 469225

Square Root: 26.1725046566048

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

Inverse Euler transform of primes. A30010

5th differences of partition numbers A000041. A81095

a(n) = ∑_{d divides n} (-1)^{d + n/d} * d². A321558

Expansion of 1/(1 - x + x⁴). A99530

Expansion of χ(q⁵) * χ(q¹⁰) / ( χ(q) * χ(q²)) in powers of q where χ() is a Ramanujan θ function. A128763

a(0) = -1; a(1) = 0; a(2) = 1; a(3) = -1; a(n) = a(n-1) - 3·a(n-2) + 3·a(n-3) - a(n-4). A141577

a(n) = ∑_d∣n (-1)^n/d-1 * binomial(d+n/d-1, d). A344777

First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 145", based on the 5-celled von Neumann neighborhood. A270289

First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 326", based on the 5-celled von Neumann neighborhood. A271262

Triangle T(n, m) appearing in the expansion of Jacobi's elliptic function cn(u, k) divided by cos(v) in terms of the Jacobi nome q and even powers of 2·cos(v) with v = u/((2/π)*K(k)). A275791