Properties of the Number -1660

Six Hundred Sixty

Basics

Value: -1661 → -1660 → -1659

Parity: even

Prime: No

Previous Prime:

Next Prime: 1

Digit Sum: 13

Digital Root: 4

Palindrome: No

Factorization: 2 ² × 5 × 83

Divisors: 1, 2, 4, 5, 10, 20, 83, 166, 332, 415

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: -11001111100

Octal: -3174

Duodecimal: -B64

Hexadecimal: -67c

Square: 2755600

Square Root: 40.74309757492672

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

a(n) = ∑_k=1..n floor(n/k) * (-3)^k-1. A344818

Square array A(n,k), n >= 1, k >= 0, read by antidiagonals downwards, where A(n,k) = ∑_j=1..n floor(n/j) * (-k)^j-1. A344824

Expansion of (1+4x-sqrt(1+4x²))/(4+6x) in powers of x. A86990

Row sums of triangle A132898. A132899

First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 419", based on the 5-celled von Neumann neighborhood. A272048

Symmetrical triangle sequence from polynomials: q(x,n)=-((-1)ⁿ*(Sum[(k + 1)ⁿ*x^k/k², {k, 1, Infinity}] - PolyLog[2, x])*(x - 1)^{n - 1} + (-1)ⁿ*n *(-1 + x)^{n - 1} Log[1 - x])/x; p(x,n)=q(x,n)+xⁿ*q(1/x,n). A154991

Triangle T(n,k) which contains 16·n!*2^floor((n+1)/2) times the coefficient [tⁿ x^k] exp(t·x)/(15 + exp(8·t)) in row n, column k. A171685

Coordination sequence T1 for Zeolite Code ABW and ATN. A8000

Generalized 10-gonal numbers: m*(4·m - 3) for m = 0, +- 1, +- 2, +- 3, ... A74377

a(n) is the limiting term of the n-th column of the triangle in A188919. A188920