Properties of the Number 18817

Eighteen Thousand Eight Hundred Seventeen

Basics

Value: 18816 → 18817 → 18818

Parity: odd

Prime: No

Previous Prime: 18803

Next Prime: 18839

Digit Sum: 25

Digital Root: 7

Palindrome: No

Factorization: 31 × 607

Divisors: 1, 31, 607, 18817

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 100100110000001

Octal: 44601

Duodecimal: AA81

Hexadecimal: 4981

Square: 354079489

Square Root: 137.17507062145074

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(0) = 1, a(1) = 2, a(n) = 4·a(n-1) - a(n-2). A1075

a(2·n) = a(2·n-1) + a(2·n-2), a(2·n+1) = 2·a(2·n) + a(2·n-1); a(0) = a(1) = 1. A2531

a(n) = (1 + a(n-1)*a(n-2))/a(n-3), a(0) = a(1) = a(2) = 1. A5246

Numbers k such that any group of k consecutive integers has integral standard deviation (viz. A011944(k)). A11943

Number of totally transitive rooted trees with n nodes. A318185

a(n) = 2·a(n-1)² - 1, starting a(0) = 2. A2812

a(n) = ChebyshevT(4, n). A144130

Array of (kⁿ + k^-n)/2 where k = (sqrt(x²-1) + x)² for integers x >= 1. A188644

Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where A(n,k) is Chebyshev polynomial of the first kind T_n(x), evaluated at x=k. A322836

a(n) = cos(2·n*arccos(sqrt(n))). A173148