Special properties of number 20 (Today’s Date)

1. 20 = 2 + 4 + 6 + 8
2. 20 = 1 + 3 + 6 + 10. i.e. 1 + (1 + 2) + (1 + 2 + 3 ) + (1 + 2 + 3 + 4 )
3. 20 is an Abundant Number. In number theory, an abundant number or excessive number is a number for which the sum of its proper divisors is greater than the number itself. The first few abundant numbers are 12, 18, 20, 24, 30, 36, ... There are only 21 abundant numbers less than 100, and they are all even. 
4. 20 is a Tetrahedral Number.
5. One month in the religious Mayan calendar contained twenty days.
6. 20 is the base of the ancient Mayan numeral system.
7. A set of 20 units may also be referred to as a score.
8. The Chemical Element Calcium has an atomic number of 20.