Properties of the Number 18909

Eighteen Thousand Nine Hundred Nine

Basics

Value: 18908 → 18909 → 18910

Parity: odd

Prime: No

Previous Prime: 18899

Next Prime: 18911

Digit Sum: 27

Digital Root: 9

Palindrome: No

Factorization: 3 ² × 11 × 191

Divisors: 1, 3, 9, 11, 33, 99, 191, 573, 1719, 2101

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 100100111011101

Octal: 44735

Duodecimal: AB39

Hexadecimal: 49dd

Square: 357550281

Square Root: 137.5099996363901

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) = a(n-1) + 2·n² with a(1) = 1. A112524

Number of n X 2 -1,1 arrays such that the sum over i=1..n, j=1..2 of i·x(i,j) is zero, the sum of x(i,j) is zero, and rows are nondecreasing (number of ways to distribute 2-across galley oarsmen left-right at n fore-aft positions so that there are no turning moments on the ship). A225338

Numbers n such that n divides the (right) concatenation of all numbers <= n written in base 17 (most significant digit on right). A29510

Ascending sequence of numbers such that the sum of any two distinct elements (even + odd) is a prime number. A180743

E.g.f.: tanh(log(1+x))*cos(x). A9776

E.g.f. tanh(log(1+x))*cosh(x). A9777

Numbers n such that 259·2ⁿ-1 is prime. A50888

a(n) = ∑_k=0..n A059432(n,k). A341647

Define the sequence S(a₀,a₁) by a_n+2 is the least integer such that a_n+2/a_n+1>a_n+1/a_n for n >= 0. This is S(3,6). A18909

Taxicab palindromes: palindromes in base 10 that are the sum of two positive cubes in more than one way. A265448