Properties of the Number 18666

Eighteen Thousand Six Hundred Sixty-Six

Basics

Value: 18665 → 18666 → 18667

Parity: even

Prime: No

Previous Prime: 18661

Next Prime: 18671

Digit Sum: 27

Digital Root: 9

Palindrome: No

Factorization: 2 × 3 ² × 17 × 61

Divisors: 1, 2, 3, 6, 9, 17, 18, 34, 51, 61

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 100100011101010

Octal: 44352

Duodecimal: A976

Hexadecimal: 48ea

Square: 348419556

Square Root: 136.6235704408284

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

Array read by antidiagonals: T(m,n) is the number of m X n binary arrays with all 1's connected and a path of 1's from top row to bottom row. A359574

Beastly (or hateful) numbers: numbers containing the string 666 in their decimal expansion. A51003

Number of n X 3 binary arrays with all 1's connected and a path of 1's from top row to bottom row. A163029

a(n) = 1·2*3 - 4·5*6 + 7·8*9 - 10·11·12 + 13·14·15 - ... + (up to n). A319543

a(n) = 3·2*1 - 6·5*4 + 9·8*7 - 12·11·10 + 15·14·13 - 18·17·16 + ... - (up to the n-th term). A319886

First term of the n-th differences of the squarefree numbers. Inverse zero-based binomial transform of A005117. A377041

Number of nonisomorphic graded posets with 0 and non-uniform Hasse graph of rank n, with exactly 2 elements of each rank above 0. A206947

Expansion of 1/((1 - x² - x³)² - 4·x⁵). A376723

a(n) = n*(n+1)*(n² - 3·n + 6)/4. A62026

Number of partitions p = [x(1), ..., x(k)], where x(1) >= x(2) >= ... >= x(k), of n such that max(x(i) - x(i-1)) is a part of p. A241735