Fatto generale: 15838 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 15838 is an uninteresting number.
Trivia: 15838 is an unremarkable number.
Data storica: May 12th is the day in 1958 that a formal North American Aerospace Defense Command agreement is signed between the United States and Canada.