General fact: 1624 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 1624 is the Stirling number of the first kind s(7,3).
Trivia: 1624 is an uninteresting number.
Historical date: June 11th is the day in 1345 that the megas doux Alexios Apokaukos, chief minister of the Byzantine Empire, is lynched by political prisoners.