Ash decides to buy 100 of each Pikachu, because he is rich. 33 are male, and 37 are female. Ash wants his own Pikachu family. If a Pikachu family includes 25 males, and 25 females, how many distinct Pikachu families are there? Divide your answer by 10^13, and round to the nearest whole number.
Details and Assumptions
All Pikachus are different. The order of Pikachus in the family does not matter.