Properties of the Number 1645

One Thousand Six Hundred Forty-Five

Basics

Value: 1644 → 1645 → 1646

Parity: odd

Prime: No

Previous Prime: 1637

Next Prime: 1657

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

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

Generalized Stirling number triangle of first kind read by rows: T(n, k) = [x^k] ∏_m=1..n (x - m - r), with r = 7. A51379

Super-3 Numbers (3n³ contains substring '333' in its decimal expansion). A14569

Number of ON states after n generations of cellular automaton rule described by the rulestring B1/S012345678. A151725

d(n,s) = number of perfect matchings on {1, 2, ..., n} with s short pairs. A79267

Sum of the n-th maximal antirun of odd primes differing by more than two. A373405

T(n,k) = Number of (n+2) X (k+2) 0..1 arrays with each row divisible by 5 and each column divisible by 7, read as a binary number with top and left being the most significant bits. A262759