Properties of the Number -221

Two Hundred Twenty-One

Basics

Value: -222 → -221 → -220

Parity: odd

Prime: No

Previous Prime:

Next Prime: 1

Digit Sum: 5

Digital Root: 5

Palindrome: No

Factorization: 13 × 17

Divisors: 1, 13, 17, 221

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: -11011101

Octal: -335

Duodecimal: -165

Hexadecimal: -dd

Square: 48841

Square Root: 14.866068747318506

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

Coefficients of the 3rd-order mock θ function f(q). A25

Values of n such that L(1) and N(1) are both prime, where L(k) = (n²+n+1)*2^2·k + (2·n+1)*2^k + 1, N(k) = (n²+n+1)*2^k + n. A226921

T(n,m), numerators of coefficients in a power/Fourier series expansion of the plane pendulum's exact phase space trajectory. A273506

a(n) = 13·a(n-1) - 65·a(n-2) + 156·a(n-3) - 182·a(n-4) + 91·a(n-5) - 13·a(n-6), with initial terms 0, 0, -1, -8, -45, -221. A216540

Triangle, read by rows, equal to the matrix inverse of Q=A113381. A114158

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

Coefficient of q²ⁿ in the series expansion of Ramanujan's mock θ function f(q). A39

G.f.: ∑_n>=0 (xⁿ - 1)ⁿ * xⁿ / (1-x)ⁿ⁺¹. A243919

Expansion of ∏_k>=1 (1 - x^k * (1 + x)). A306565

A linear mapping a(n) = x + d·n of pairs of integers (x,d), where the pairs are enumerated by a number spiral along antidiagonals. A304587