Fatto generale: 4963 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 4963 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Trivia: 4963 is an uninteresting number.
Data storica: August 2nd is the day in 1939 that Albert Einstein and Leó Szilárd write a letter to Franklin D. Roosevelt, urging him to begin the Manhattan project to develop a nuclear weapon.