Properties of the Number 18857

Eighteen Thousand Eight Hundred Fifty-Seven

Basics

Value: 18856 → 18857 → 18858

Parity: odd

Prime: No

Previous Prime: 18839

Next Prime: 18859

Digit Sum: 29

Digital Root: 2

Palindrome: No

Factorization: 109 × 173

Divisors: 1, 109, 173, 18857

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 100100110101001

Octal: 44651

Duodecimal: AAB5

Hexadecimal: 49a9

Square: 355586449

Square Root: 137.32079230764728

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

O.g.f.: ∑_n>=0 1/(1-n²*x)ⁿ * xⁿ/n! * exp(-x/(1-n²*x)). A218668

Odd semiprimes p·q, such that Stern polynomial B(p·q,x) is a product of B(p,x) and B(q,x). A391256

a(n) = ∑_y=1..n ∑_x=1..n floor((x^k + y^k)^1/k) with k = 2. A211791

Index of the smaller Ulam number of record gaps (A080287). A274522

Expansion of (1/x) * Series_Reversion( x*(1-x)³/(1-x-x²) ). A366082

Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 123", based on the 5-celled von Neumann neighborhood. A270212

a(n) = a(n-1) + 3·a(n-2) -2·a(n-3) - 2·a(n-4), where a(0) = 1, a(1) = -2, a(2) = 2, a(3) = 1. A295855

Number of partitions of n satisfying cn(0,5) = cn(2,5) + cn(3,5). A39859

Ulam numbers: a(1) = 1; a(2) = 2; for n>2, a(n) = least number > a(n-1) which is a unique sum of two distinct earlier terms. A2858

Smallest power of 3 that begins with n. A18857