Properties of the Number 18506

Eighteen Thousand Five Hundred Six

Basics

Value: 18505 → 18506 → 18507

Parity: even

Prime: No

Previous Prime: 18503

Next Prime: 18517

Digit Sum: 20

Digital Root: 2

Palindrome: No

Factorization: 2 × 19 × 487

Divisors: 1, 2, 19, 38, 487, 974, 9253, 18506

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 100100001001010

Octal: 44112

Duodecimal: A862

Hexadecimal: 484a

Square: 342472036

Square Root: 136.0367597379473

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

G.f.: ∏_{i>=1, j>=1, k>=1, l>=1} (1 + x^i·j*k·l). A280486

1 - 1/a(n) is the largest resistance value of this form that can be obtained from a resistor network of not more than n one-ohm resistors. A339548

Distinct perimeter lengths of polygons with regularly spaced vertices. A7874

Constant term of the reduction by x²->x+1 of the polynomial p(n,x) defined at Comments. A193044

Ordered differences of numbers 3^j-2^j, as in A001047. A205105

Number of (7+2) X (n+2) 0..3 arrays with every 3 X 3 subblock row and diagonal sum equal to 0 3 5 6 or 7 and every 3 X 3 column and antidiagonal sum not equal to 0 3 5 6 or 7. A252391

Numbers k such that there exists i >= 1 such that k divides 3³^i + 1. A367266

Composite numbers k such that (Bell(k+1) - Bell(k)) mod k = 1. A179279

a(n) = index of 2·prime(n) in A381019. A379811

Irregular triangle read by rows: row n consists of the coefficients in the expansion of the polynomial (1/(2·w)) * (x² + x) * ((((v + w)/2)^{n - 1}) * (x² + 2·x + 4 + w) - (((v - w)/2)^{n - 1}) * (x² + 2·x + 4 - w)), where v = x² + 4·x + 4 and w = sqrt(x⁴ + 4·x³ + 12·x² + 20·x + 12). A386874