Fatto generale: 2543 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 2543 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Trivia: 2543 is an unremarkable number.
Data storica: December 17th is the day in 1967 that Prime Minister of Australia Harold Holt disappears while swimming near Portsea, Victoria and is presumed drowned.