Properties of the Number -1980

Nine Hundred Eighty

Basics

Value: -1981 → -1980 → -1979

Parity: even

Prime: No

Previous Prime:

Next Prime: 1

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

Triangle read by rows: T(n, k) = (-1)^k+1*binomial(n,k)*binomial(n+k,k) (n >= k >= 0). A331430

a(n) = 6ⁿ/n! * ∏_k=0..n-1 (6·k - 1). A4996

Triangular table containing values of coefficients of the characteristic polynomial of a certain n·n circulant matrix, read by rows. A127412

Expansion of g.f. A(x) = G( x*(1 + 2·x)*G(x) )^1/2 = G( x*(1 + 3·x)*G(x)² )^1/3, where G(x) is the g.f. of A370537. A370538

Convolution array for Chebyshev's S(n,x)=U(n,x/2) polynomials. A128502

Triangle of signed numbers used for the computation of the column sequences of triangle A090217. A90435

Triangle read by rows: Riordan array (1/(1-9x)^2/3, x/(9x-1)). A283151

Expansion of determinant of 24 X 24 matrix M_u,v = q^{maj(u·v^-1}) where u, v in S₄ and maj = MacMahon's major index (cf. A008302). A323978

McKay-Thompson series of class 5a for Monster. A7253

Triangle of diagonals of symmetric Krawtchouk matrices. A99037