Fatto generale: 72639 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 72639 is a boring number.
Trivia: 72639 is an unremarkable number.
Data storica: November 17th is the day in 1990 that Fugendake, part of the Mount Unzen volcanic complex, Nagasaki prefecture, Japan becomes active again and erupts.