Properties of the Number -1281

Two Hundred Eighty-One

Basics

Value: -1282 → -1281 → -1280

Parity: odd

Prime: No

Previous Prime:

Next Prime: 1

Digit Sum: 12

Digital Root: 3

Palindrome: No

Factorization: 3 × 7 × 61

Divisors: 1, 3, 7, 21, 61, 183, 427, 1281

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: -10100000001

Octal: -2401

Duodecimal: -8A9

Hexadecimal: -501

Square: 1640961

Square Root: 35.79106033634656

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

Let c(n) = x^2ⁿ-1*(1-x^2ⁿ), g(n) = 1 + x^2ⁿ-1 + x^2ⁿ, h(n) = ∏_i=1..n g(i); then use g.f. (1+2·x) - ∑_n>=1 c(n)/h(n). A151684

Expansion of ∏_k>0 (1 - d(k)*x^k), where d(k) is the number of divisors of k. A321619

Coefficients of period polynomials. A6309

Moser-de Bruijn sequence: sums of distinct powers of 4. A695

Octagonal numbers: n*(3·n-2). Also called star numbers. A567

Generalized octagonal numbers: k*(3·k-2), k=0, +- 1, +- 2, +-3, ... A1082

a(n) = ∑_k=1..n n/gcd(n,k). A57660

Sum of divisors of square numbers. A65764

Square array, read by antidiagonals, where row n equals the crystal ball sequence for the A_n lattice. A108625

Number of integer partitions of n that are empty, (1), or have at least two parts and these parts are pairwise coprime. A327516