Properties of the Number -642

Six Hundred Forty-Two

Basics

Value: -643 → -642 → -641

Parity: even

Prime: No

Previous Prime:

Next Prime: 1

Digit Sum: 12

Digital Root: 3

Palindrome: No

Factorization: 2 × 3 × 107

Divisors: 1, 2, 3, 6, 107, 214, 321, 642

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

5184 Try Today's Challenge

Representations

Binary: -1010000010

Octal: -1202

Duodecimal: -456

Hexadecimal: -282

Square: 412164

Square Root: 25.337718918639855

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

Expansion of (1-x-x^N)/((1-x)(1-x²)(1-x³)...(1-x^N)) for N = 9. A60028

McKay-Thompson series of class 24d for Monster. A58587

Partition function coefficients for square lattice spin 1 Ising model. A10107

Matrix inverse of triangle A122177, where A122177(n,k) = C( k*(k+1)/2 + n-k + 2, n-k) for n>=k>=0. A121437

Output of Knuth's "man or boy" test for varying k. A132343

Expansion of g.f.: 2^floor((n+1/2))*n!*(1-y)ⁿ⁺¹*f(x, y, m), where f(x, y, m) = 2^m+1*exp(2^m*t)/((1-y·exp(t))*(1 + (2^m+1-1)*exp(2^m*t))), and m = 1. A171695

∏_n>=1 (1 + xⁿ)^a(n) = 1 + ∑_n>=1 x^prime(n). A328777

G.f.: 1/(1 + (x+x² + x)/(1 + (x+x² + x²)/(1 + (x+x² + x³)/(1 + (x+x² + x⁴)/(1 + ...))))), a continued fraction. A352234

Values of L(2ⁿ), where L(n) is the summatory function of the Liouville function A008836(n). A390483

A symmetrical triangle:q=4;c(n,q)=Product[1 - qⁱ, {i, 1, n}];t(n,m,q)=A060187(n,m)-c(n,q)/(c(m,q)*c(n-m,q))+1. A176469