Properties of the Number -1645

Six Hundred Forty-Five

Basics

Value: -1646 → -1645 → -1644

Parity: odd

Prime: No

Previous Prime:

Next Prime: 1

Digit Sum: 16

Digital Root: 7

Palindrome: No

Factorization: 5 × 7 × 47

Divisors: 1, 5, 7, 35, 47, 235, 329, 1645

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: -11001101101

Octal: -3155

Duodecimal: -B51

Hexadecimal: -66d

Square: 2706025

Square Root: 40.55859958134649

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

E.g.f.: exp(1 + x + x²/2! - exp(x)). A293038

Stirling transform of the first kind of the Lucas numbers A000032. A213593

A measure of how close rⁿ is to an integer where r is the real root of x³-x-1, i.e.. r = (1/2 + sqrt(23/108))^1/3 + (1/2 - sqrt(23/108))^1/3 = 1.3247.... (Higher absolute value of a(n) means closer, negative means less than closest integer.) A84252

Numerator of Bernoulli(n, -3/4). A157860

First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 443", based on the 5-celled von Neumann neighborhood. A272228

Let f(x) = 1 + x² + x⁴ + x⁵ + x⁶ + x¹⁰ + x¹¹; sequence has g.f. g(x) = 1/(x¹¹*f(1/x)). A157876

Y-toothpick sequence (see Comments lines for definition). A160120

Triangle of numbers related to triangle A092083; generalization of Stirling numbers of second kind A008277, Lah-numbers A008297, ... A92082

Integers of the form t/6, where t is a triangular number (A000217). A154293

a(n) = n*(n + 12). A98847