Properties of the Number 1980

One Thousand Nine Hundred Eighty

Basics

Value: 1979 → 1980 → 1981

Parity: even

Prime: No

Previous Prime: 1979

Next Prime: 1987

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 2 ² × 3 ² × 5 × 11

Divisors: 1, 2, 3, 4, 5, 6, 9, 10, 11, 12

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 11110111100

Octal: 3674

Duodecimal: 1190

Hexadecimal: 7bc

Square: 3920400

Square Root: 44.49719092257398

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

Oblong (or promic, pronic, or heteromecic) numbers: a(n) = n*(n+1). A2378

Highly abundant numbers: numbers k such that σ(k) > σ(m) for all m < k. A2093

a(n) = 2·n*(2·n+1). A2943

T(n,k) = binomial(n,k)*binomial(n+k,k), 0 <= k <= n, triangle read by rows. A63007

Expansion of g.f.: (1+x)/(1-44·x). A170764

a(n) = lcm{1,2,...,n} / swinging_factorial(n) = A003418(n) / A056040(n). A180000

e-perfect numbers: numbers k such that the sum of the e-divisors (exponential divisors) of k equals 2·k. A54979

Denominators of Cauchy numbers of first type. A6233

Numbers k such that σ(k) > 3·k. A68403

Coreful perfect numbers: numbers k such that csigma(k) = 2·k, where csigma(k) is the sum of the coreful divisors of k (A057723). A307958