Fatto matematico: 2394 is the smallest value of n for which n and 7n together use each digit 1-9 exactly once.
Trivia: 2394 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: July 21st is the day in 1925 that Sir Malcolm Campbell becomes the first man to break the 150 mph (241 km/h) land barrier at Pendine Sands in Wales.