Fatto generale: 17639 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 17639 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Trivia: 17639 is a boring number.
Data storica: April 16th is the day in 1962 that Walter Cronkite takes over as the lead news anchor of the CBS Evening News, during which time he would become "the most trusted man in America".