Fatto generale: 63938 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 63938 is a boring number.
Trivia: 63938 is an uninteresting number.
Data storica: January 20th is the day in 1972 that Pakistan launched its Nuclear detterent program few weeks after its defeat in Bangladesh Liberation War and Indo-Pakistani War of 1971.