Properties of the Number -18980

Eighteen Thousand Nine Hundred Eighty

Basics

Value: -18981 → -18980 → -18979

Parity: even

Prime: No

Previous Prime:

Next Prime: 1

Digit Sum: 26

Digital Root: 8

Palindrome: No

Factorization: 2 ² × 5 × 13 × 73

Divisors: 1, 2, 4, 5, 10, 13, 20, 26, 52, 65

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: -100101000100100

Octal: -45044

Duodecimal: -AB98

Hexadecimal: -4a24

Square: 360240400

Square Root: 137.7679207943562

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) = ∑_{d∣n, d==1 mod 4} d³ - ∑_{d∣n, d==3 mod 4} d³. A50459

a(n) = (-1)ⁿ*n*(n+1)*(2·n-5)/6. A167386

a(n) = ∑_{d∣n, n/d=1 mod 4} d³ - ∑_{d∣n, n/d=3 mod 4} d³. A50471

a(n) = n³ - n² + n - 1 = (n-1) * (n² + 1). A62158

T(n,k)=Number of nXk 0..1 arrays with rows, diagonals and antidiagonals unimodal. A223669

Square array T(n,k), n >= 2, k >= 2, read by antidiagonals, where T(n,k) is the number of Hamiltonian circuits within parallelograms of size n X k on the triangular lattice. A339849

a(n) = (1/6)*(2·n - 3)*(n + 2)*(n + 1). A58373

Numbers k such that iphi(k) = iphi(k+1), where iphi(k) is an infinitary analog to the Euler totient function (A091732). A326403

Number of partitions of n such that the least part occurs exactly five times. A97093

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