Properties of the Number 17815

Seventeen Thousand Eight Hundred Fifteen

Basics

Value: 17814 → 17815 → 17816

Parity: odd

Prime: No

Previous Prime: 17807

Next Prime: 17827

Digit Sum: 22

Digital Root: 4

Palindrome: No

Factorization: 5 × 7 × 509

Divisors: 1, 5, 7, 35, 509, 2545, 3563, 17815

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 100010110010111

Octal: 42627

Duodecimal: A387

Hexadecimal: 4597

Square: 317374225

Square Root: 133.47284367990366

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

n satisfying σ(n+1) = σ(n-1). A55574

G.f. satisfies: A(x·g(x)) = g(x) where g(x) is the g.f. of A088716. A88715

E.g.f. A(x) satisfies A(x) = exp(x(A(x)-2)). A97718

Expansion of ∑_i>=1 i·xⁱ/(1 - x) * ∏_j=1..i 1/(1 - x^j). A284870

Wiener index of a benzenoid consisting of a double-step spiral chain of n hexagons (n>=2, s=21; see the Gutman et al. reference). A193397

Numbers k such that σ(k-1) divides σ(k+1). A67130

Odd composite integers m such that U(m)² == 1 (mod m) and V(m) == 4 (mod m), where U(m)=A001353(m) and V(m)=A003500(m) are the m-th generalized Lucas and Pell-Lucas numbers of parameters a=4 and b=1, respectively. A337778

a(n) = ∑_{k=1 to d(n)} C(d(n)-1, k-1) d_k, where d(n) is the number of divisors of n and d_k is the k-th divisor of n. A132065

Numbers n such that σ(n+1) - σ(n-1) = k·n for some integer k, where σ(n) = A000203 (sum of divisors of n). A223137

Numbers k such that σ(k+1) divides σ(k-1). A227304