Properties of the Number 18945

Eighteen Thousand Nine Hundred Forty-Five

Basics

Value: 18944 → 18945 → 18946

Parity: odd

Prime: No

Previous Prime: 18919

Next Prime: 18947

Digit Sum: 27

Digital Root: 9

Palindrome: No

Factorization: 3 ² × 5 × 421

Divisors: 1, 3, 5, 9, 15, 45, 421, 1263, 2105, 3789

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 100101000000001

Octal: 45001

Duodecimal: AB69

Hexadecimal: 4a01

Square: 358913025

Square Root: 137.64083696345355

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

a(n) = ∑_k=0..n n^n-k * kⁿ. A368505

Numbers n such that h(n) = 3 h(n-1) where h(n) is the length of the sequence {n, f(n), f(f(n)), ...., 1} in the Collatz (or 3x + 1) problem. (The earliest "1" is meant.) A78420

Number of parts that are multiples of 3 in all partitions of n. A116635

a(n) = 74·n² + 1. A158742

a(n) = 5ⁿ*∑_i=1..n i⁵/5ⁱ. A218376

Square array T(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where T(n,k) = ∑_j=0..n k^n-j * j^k. A368504

Expansion of (1 + 6·x + x² + 12·x³ - 2·x⁴)/((1 - x)⁴*(1 + x)³). A268579

Number of (n+2)X(2+2) 0..3 arrays with every 3X3 subblock row and column sum not 0 1 2 7 8 or 9 and every diagonal and antidiagonal sum 0 1 2 7 8 or 9. A251977

Cycle class sequence c(2n) (the number of true cycles of length 2n in which a certain node is included) for zeolite AEL = AlPO4-11 [Al20P20O80] starting with a T1 atom. A18945