Properties of the Number 1665

One Thousand Six Hundred Sixty-Five

Basics

Value: 1664 → 1665 → 1666

Parity: odd

Prime: No

Previous Prime: 1663

Next Prime: 1667

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 3 ² × 5 × 37

Divisors: 1, 3, 5, 9, 15, 37, 45, 111, 185, 333

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 11010000001

Octal: 3201

Duodecimal: B69

Hexadecimal: 681

Square: 2772225

Square Root: 40.80441152620633

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

Centered tetrahedral numbers. A5894

Number of potential flows in 3 X 3 array with integer velocities in -n..n, i.e., number of 3 X 3 arrays with adjacent elements differing by no more than n, counting arrays differing by a constant only once. A68744

a(n) = floor(n(n+2)(2n+1)/8). A2717

Integers of the form m*(m + 6)/7. A274978

D-toothpick sequence of the third kind starting with a single toothpick. A220500

a(n) = n*(n+8). A28566

Generalized Stirling number triangle of first kind read by rows: T(n, k) = [x^k] ∏_m=1..n (x - m - r), with r = 1. A49444

Numerator of 1/16 - 1/n². A61041

Dispersion of A008851, (numbers >1 and congruent to 0 or 1 mod 5), by antidiagonals. A191722

Numbers where 6 outnumbers any other digit. A292456