Properties of the Number 18020

Eighteen Thousand Twenty

Basics

Value: 18019 → 18020 → 18021

Parity: even

Prime: No

Previous Prime: 18013

Next Prime: 18041

Digit Sum: 11

Digital Root: 2

Palindrome: No

Factorization: 2 ² × 5 × 17 × 53

Divisors: 1, 2, 4, 5, 10, 17, 20, 34, 53, 68

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 100011001100100

Octal: 43144

Duodecimal: A518

Hexadecimal: 4664

Square: 324720400

Square Root: 134.23859355639868

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

Number of connected regular graphs with n nodes and girth at least 4. A186724

T(n,k)=Number of nXk 0..1 arrays with no element equal to more than two of its horizontal, diagonal or antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards. A281563

a(n) = ∏_{d∣n, d-1 is prime} (d-1)^{1+A286561(n,d-1}), where A286561(n,k) gives the k-valuation of n (for k > 1). A323155

Expansion of g.f. A(x) satisfying A(x) = 1 + x*(3·A(x)² - A(-x)²)/2. A368634

Practical numbers z such that z² = x² + y² for some practical numbers·and y with gcd(x,y,z) = 4. A294112

a(n) = 1000·n + 20. A157510

a(n) = n*(2·n² + 5·n + 1). A163832

The first Zagreb index of the Aztec diamond AZ(n) (see the Ramanes et al. reference, Theorem 2.1). A292344

a(n)=f(a(n-1),a(n-2)+1,a(n-3)), where f(x,y,z)=yz+zx+xy and (a(1),a(2),a(3))=(0,0,1). A203762

a(n) = 4*(n - 1)*(16·n - 23) for n >= 1. A304378