Fatto matematico: 7884 is a value of n for which 2n and 5n together use each digit exactly once.
Trivia: 7884 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: August 1st is the day in 1980 that Vigdís Finnbogadóttir is elected President of Iceland and becomes the country's first democratically elected female head of state.