Properties of the Number 20508

Twenty Thousand Five Hundred Eight

Basics

Value: 20507 → 20508 → 20509

Parity: even

Prime: No

Previous Prime: 20507

Next Prime: 20509

Digit Sum: 15

Digital Root: 6

Palindrome: No

Factorization: 2 ² × 3 × 1709

Divisors: 1, 2, 3, 4, 6, 12, 1709, 3418, 5127, 6836

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101000000011100

Octal: 50034

Duodecimal: BA50

Hexadecimal: 501c

Square: 420578064

Square Root: 143.20614511954437

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 T(n, k) = Numbers of ways to place k points on a triangular grid of side n so that no three of them are vertices of an equilateral triangle with sides parallel to the grid. Triangle read by rows. A243211

Decimal representation of the x-axis, from the left edge to the origin, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 169", based on the 5-celled von Neumann neighborhood. A279547

Triangle of coefficients of polynomials u(n,x) jointly generated with A208762; see the Formula section. A208761

Integers k such that k² is not a palindrome and the square root of the reverse of k² yields an integer with the same number of digits as k that is not the reverse of k. A284986

Irregular square reversible numbers. Numbers which when squared and written backwards give a square again, but don't satisfy reverse(n²) = reverse(n)². A129914

Cyclotomic polynomials at x=-9. A20508

Number of ways to place 7 nonattacking knights on an n X n toroidal board. A173436

Number of (n+1)X3 0..5 arrays with column and row pair sums b(i,j)=a(i,j)+a(i,j-1) and c(i,j)=a(i,j)+a(i-1,j) nondecreasing in column and row directions, respectively. A203938

a(n) = A284986(n)². A319570