Properties of the Number -20490

Twenty Thousand Four Hundred Ninety

Basics

Value: -20491 → -20490 → -20489

Parity: even

Prime: No

Previous Prime:

Next Prime: 1

Digit Sum: 15

Digital Root: 6

Palindrome: No

Factorization: 2 × 3 × 5 × 683

Divisors: 1, 2, 3, 5, 6, 10, 15, 30, 683, 1366

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: -101000000001010

Octal: -50012

Duodecimal: -BA36

Hexadecimal: -500a

Square: 419840100

Square Root: 143.1432848582147

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

T(n,k) = Number of (n+1) X (k+1) 0..3 arrays with every 2 X 2 subblock summing to 6 and no 2 X 2 subblock having exactly two nonzero entries. A251236

Composite numbers equal to the sum of the prime factors, with multiplicity, of the previous k numbers, for some k. A257525

Expansion of g/(1 - x⁴*g⁴), where g = 1+x·g² is the g.f. of A000108. A391035

Numbers equal to the sum of the prime factors, with multiplicity, of the previous k numbers, for some k. A257976

Numbers k such that k + sum of its prime factors = (k+1) + sum of its prime factors. A20700

Triangle read by rows: t(n,m) = ∑_i=0..n (-1)^m-i*Eulerian1(n-i+1, m-i) *Stirling2(n+i+1, i+1), where Eulerian1 are the Eulerian numbers of the first kind (A173018). A156364

Generalized Narayana triangle for secant. A180959

Expansion of 1/( (1 + x) * (1 - x²*(1 + x)³) ). A375364

Numbers n such that n + sum of prime factors of n = (n+1) + sum of prime factors of (n+1). A75654

Antidiagonal sums of A147995 and A163545. A163484