Properties of the Number -1644

Six Hundred Forty-Four

Basics

Value: -1645 → -1644 → -1643

Parity: even

Prime: No

Previous Prime:

Next Prime: 1

Digit Sum: 15

Digital Root: 6

Palindrome: No

Factorization: 2 ² × 3 × 137

Divisors: 1, 2, 3, 4, 6, 12, 137, 274, 411, 548

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: -11001101100

Octal: -3154

Duodecimal: -B50

Hexadecimal: -66c

Square: 2702736

Square Root: 40.54626986542659

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) = 4·3*2·1 - 8·7*6·5 + 12·11·10·9 - 16·15·14·13 + ... - (up to the n-th term). A319887

Coefficient table for sums of squares of Chebyshev's S-Polynomials. A128495

a(n) = coefficient of x^2·n in A(x) = 1 + ∑_n>=1 (-1)ⁿ * x^4·n² * (F(x/2)^2·n + F(-x/2)^2·n), where F(x) is the g.f. of A357787. A357806

a(n) = ∑_{k=0..floor(n/5)} (-1)^k * (n-4·k)!/(n-5·k)!. A358606

Expansion of 1/( (1-x)*(1 + x² + x³) ). A77889

a(n) = -a(n-1) -a(n-2) -a(n-3) +a(n-4), a(0)=0, a(1)=1, a(2)=-1, a(3)=0. A100329

Expansion of φ(-x³) / f(-x²) in powers of·where φ(), f() are Ramanujan θ functions. A256636

T(n, k) = Stirling1(n+1, k) - Stirling1(n, k-1), for 1 <= k <= n. Triangle read by rows. A94485

Triangle read by rows: T(n,k) (1 <= k <= n) given by T(n,1) = T(n,n) = 1, otherwise T(n,k) = (m·n-m·k+1)*T(n-1,k-1) + (m·k-m+1)*T(n-1,k), where m = -5. A392666

First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 149", based on the 5-celled von Neumann neighborhood. A270320