Properties of the Number 81090

Eighty-One Thousand Ninety

Basics

Value: 81089 → 81090 → 81091

Parity: even

Prime: No

Previous Prime: 81083

Next Prime: 81097

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 2 × 3 ² × 5 × 17 × 53

Divisors: 1, 2, 3, 5, 6, 9, 10, 15, 17, 18

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 10011110011000010

Octal: 236302

Duodecimal: 3AB16

Hexadecimal: 13cc2

Square: 6575588100

Square Root: 284.76305940202286

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) = 4·a(n-1) - a(n-2), with a(0) = 0, a(1) = 2. A52530

a(2n+1) = a(2n) + a(2n-1), a(2n) = 2·a(2n-1) + a(2n-2); a(n) = n for n = 0, 1. A48788

Limit of the sequence obtained from S(0) = (1,1) and, for n > 0, S(n) = I(S(n-1)), where I consists of inserting, for i = 1, 2, 3..., the term a(i) + a(i+1) between any two terms for which 7·a(i+1) <= 11·a(i). A82630

a(2·n+1) = 9·a(n), a(2·n+2) = 10·a(n) + a(n-1). A116555

Maximal term of TRIP-Stern sequence of level n corresponding to permutation triple (e,23,e). A271488

Those primitive elements of A337386 that have exactly one primitive nondeficient divisor (A006039). A341604

Expansion of g.f.: 1/∑_{p prime} x^p. A352476

Square array read by descending antidiagonals: A(n,k) is the number of fixed n-dimensional (n,2)-polyominoids, n >= 2, of size k >= 1. A385715

Expansion of (1-2x-3x²+x³-x⁵)/(1+4x³+x⁶). A157126

The pairs (x,y) such that (x² + y²)/(x·y + 1) is a perfect square, i.e., 4. A162959