Properties of the Number 20638

Twenty Thousand Six Hundred Thirty-Eight

Basics

Value: 20637 → 20638 → 20639

Parity: even

Prime: No

Previous Prime: 20627

Next Prime: 20639

Digit Sum: 19

Digital Root: 1

Palindrome: No

Factorization: 2 × 17 × 607

Divisors: 1, 2, 17, 34, 607, 1214, 10319, 20638

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101000010011110

Octal: 50236

Duodecimal: BB3A

Hexadecimal: 509e

Square: 425927044

Square Root: 143.65931922433714

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 nXk 0..2 arrays with exactly floor(nXk/2) elements unequal to at least one horizontal, diagonal or antidiagonal neighbor, with new values introduced in row major 0..2 order. A222488

Maximal elements of pairs of "Super Unitary Amicable Numbers", sorted by their minimal elements. A45614

a(n) = (n⁵ + 145·n⁴ + 905·n³ + 155·n² + 594·n + 120)/120. A143060

Number of nX5 0..2 arrays with exactly floor(nX5/2) elements unequal to at least one horizontal, diagonal or antidiagonal neighbor, with new values introduced in row major 0..2 order. A222485

Growth series for affine Coxeter group (or affine Weyl group) D₉. A266764

Square array A(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where column k is the expansion of e.g.f. B(x)^k, where B(x) is the e.g.f. of A384856. A384860

a(n) = ∑_{i=0..floor(n/2)} T(2i,n-2i), array T as in A049735. A49738

Number of 5Xn 0..2 arrays with exactly floor(5Xn/2) elements unequal to at least one horizontal, diagonal or antidiagonal neighbor, with new values introduced in row major 0..2 order. A222492

G.f.: x + sq(x/(1-x) + sq(x/(1-2·x) + sq(x/(1-3·x) + sq(x/(1-4·x) + ...)))) where sq(x) = x², an infinitely nested square. A392210

Least inverse of A001390, or 0 if no inverse exists. A20638