Properties of the Number -661

Six Hundred Sixty-One

Basics

Value: -662 → -661 → -660

Parity: odd

Prime: No

Previous Prime:

Next Prime: 1

Digit Sum: 13

Digital Root: 4

Palindrome: No

Factorization: 661

Divisors: 1, 661

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: -1010010101

Octal: -1225

Duodecimal: -471

Hexadecimal: -295

Square: 436921

Square Root: 25.709920264364882

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

Triangle T, read by rows, where all columns of T are different and yet all columns of the matrix square T² (A118407) are equal; also equals the matrix inverse of triangle A118400. A118404

G.f. A(x,y) satisfies: A(x,y) = x * (1 + y·A(x,y)*A'(x,y)) / (1 + A(x,y)*A'(x,y)), where A'(x,y) = d/dx A(x,y). A301930

Primes or negative values of primes of the form 8·n² - 298·n + 2113 for n >= 0. A217439

Primes or negative values of primes of the form 8·n² - 326·n + 2659 for n >= 0. A217440

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

a(n) = 6·n³ - 263·n² + 3469·n - 12841. A218457

Alternating sum of heptagonal pyramidal numbers. A269428

First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 201", based on the 5-celled von Neumann neighborhood. A270723

Number of compositions of n such that no two adjacent parts are equal (these are sometimes called Carlitz compositions). A3242

Greater of twin primes. A6512