An interesting fact about the number "20" is that it is the maximum number of moves to solve all possible positions of a Rubik's Cube. It is referred to as "God's Number" that was proven by Morley Davidson, John Dethridge, Herbert Kociemba and Tomas Rokicki in July, 2010.
The Ancient Mayans used the number "20" as the base for their numeral system, known as the "vigesimal" number system. In mathematics, the sum of the first four even numbers, first four triangular numbers and the first six Fibonacci numbers is 20. Twenty is also a tetrahedral number and the total number of rooted trees with six vertices.