Fatto generale: 18428 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 18428 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Trivia: 18428 is a boring number.
Data storica: June 14th is the day in 1966 that the Vatican announces the abolition of the Index Librorum Prohibitorum (index of prohibited books), which was originally instituted in 1557.