Properties of the Number -421

Four Hundred Twenty-One

Basics

Value: -422 → -421 → -420

Parity: odd

Prime: No

Previous Prime:

Next Prime: 1

Digit Sum: 7

Digital Root: 7

Palindrome: No

Factorization: 421

Divisors: 1, 421

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: -110100101

Octal: -645

Duodecimal: -2B1

Hexadecimal: -1a5

Square: 177241

Square Root: 20.518284528683193

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

Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of e.g.f.: exp(∏_j=1..n 1/(1+x^j) - 1). A294289

Expansion of 1/(1 + x*∏_k>=1 (1 - x^k)). A331484

a(n) = 1 + ∑_k=2..n (-1)^k * k·a(floor(n/k)). A361982

Expansion of (1 - x + 2·x²) / (1 - x³ + x⁴). A110062

E.g.f.: exp(1/((1+x)*(1+x²)*(1+x³)) - 1). A294291

Expansion of ∑_k>=1 μ(k)*log(1 + ∑_j>=1 x^prime(j*k))/k. A308298

Expansion of (1/(1 + x)) * ∑_k>=1 k·x^k/(x^k + (1 + x)^k). A320589

G.f. ∑_n=-oo..+oo (xⁿ - x)ⁿ⁺¹. A378582

Expansion of ψ(-q)/ψ(-q²) in powers of q where ψ() is a Ramanujan θ function. A116498

Expansion of ∏_k>=1 (1 + x^3·k)^3·k / (1 + x^k)^k. A285294