Fatto matematico: 4159 is 4^{5} + 1^{5} + 5^{5} + 9.
Trivia: 4159 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: May 21st is the day in 1994 that the Democratic Republic of Yemen unsuccessful attempts to secede from the Republic of Yemen; a war breaks out.