Properties of the Number 20725

Twenty Thousand Seven Hundred Twenty-Five

Basics

Value: 20724 → 20725 → 20726

Parity: odd

Prime: No

Previous Prime: 20719

Next Prime: 20731

Digit Sum: 16

Digital Root: 7

Palindrome: No

Factorization: 5 ² × 829

Divisors: 1, 5, 25, 829, 4145, 20725

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101000011110101

Octal: 50365

Duodecimal: BBB1

Hexadecimal: 50f5

Square: 429525625

Square Root: 143.96180048887967

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

E.g.f. satisfies: A(x) = 1 + x·A(x)²*exp(x·A(x)). A213644

Number of length-4 0..n arrays with no adjacent pair x,x+1 repeated. A269657

x-value of the smallest solution to 2·x² - p·y² = (-1)^(p+1/4), p = A002145(n). A306618

Number of two element anti-chains in Riordan trees on n edges (also called non-redundant trees, i.e., ordered trees where no vertex has out-degree equal to 1). A139263

a(n) = 10^prime(n-1) mod prime(n)². A265012

Square array, read by antidiagonal: T(n,k) = n·T(n,k-1)+(-1)^k*T(n,floor(k/2)). A89141

Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 654", based on the 5-celled von Neumann neighborhood. A273332

Integers >= 2. a(n) = n+1. A20725

E.g.f. satisfies: A(x) = exp( x·Catalan(x·A(x)) ), where Catalan(x) = (1-sqrt(1-4·x))/(2·x) is the g.f. of A000108. A161629