Properties of the Number -665

Six Hundred Sixty-Five

Basics

Value: -666 → -665 → -664

Parity: odd

Prime: No

Previous Prime:

Next Prime: 1

Digit Sum: 17

Digital Root: 8

Palindrome: No

Factorization: 5 × 7 × 19

Divisors: 1, 5, 7, 19, 35, 95, 133, 665

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: -1010011001

Octal: -1231

Duodecimal: -475

Hexadecimal: -299

Square: 442225

Square Root: 25.787593916455254

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) = (n+1)*(2-n)/2. A80956

Carlitz-Riordan q-Catalan numbers (recurrence version) for q=-9. A15106

Square array A(n,k), n>=0, k>=0, read by antidiagonals, where column k is expansion of ∏_j>=1 (1-x^j)^{j^k} in power of x. A283272

Numerators of coefficient array for minimal polynomials of sin(2*π/n). Rising powers of x. A181872

Expansion of g.f. 1+x+(1+3·x+x²)/(1+x)³. A201163

G.f.: ∑_n=-oo..+oo x^n*(n+1/2) * C(x)^2·n-1, where C(x) = 1 + x·C(x)² is the g.f. of the Catalan numbers (A000108). A355345

Square array A(n,k), n>=0, k>=0, read by antidiagonals, where column k is the expansion of ∏_j>=1 (1 - j^k*x^j). A292166

T(n,k) an additive decomposition of the signed tangent number (triangle read by rows). A154342

Expansion of exp( ∑_n>=1 -sigma₇(n)*xⁿ/n ) in powers of x. A283337

Expansion of ∏_m>=1 (1+q^m)^-5. A22600