Properties of the Number -1891

Eight Hundred Ninety-One

Basics

Value: -1892 → -1891 → -1890

Parity: odd

Prime: No

Previous Prime:

Next Prime: 1

Digit Sum: 19

Digital Root: 1

Palindrome: No

Factorization: 31 × 61

Divisors: 1, 31, 61, 1891

Polygonal

Triangular: Yes

Square: No

Pentagonal: No

Hexagonal: Yes

Heptagonal: No

Tetrahedral: No

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Representations

Binary: -11101100011

Octal: -3543

Duodecimal: -1117

Hexadecimal: -763

Square: 3575881

Square Root: 43.485629810317796

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

Row sums of a number triangle related to the Pell numbers. A110331

Expansion of 1/(1 + x*∏_k>=1 1/(1 - x^k)). A318581

First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 505", based on the 5-celled von Neumann neighborhood. A272584

First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 105", based on the 5-celled von Neumann neighborhood. A270163

First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 329", based on the 5-celled von Neumann neighborhood. A271276

First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 453", based on the 5-celled von Neumann neighborhood. A272276

First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 507", based on the 5-celled von Neumann neighborhood. A272588

Dirichlet g.f.: ζ(s) / (ζ(s-1) * ζ(s-2)). A351654

Hexagonal numbers: a(n) = n*(2·n-1). A384

a(n) = n + (n+1)². A28387