Fatto generale: 16858 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 16858 is an uninteresting number.
Trivia: 16858 is an unremarkable number.
Data storica: February 25th is the day in 1797 that Colonel William Tate and his force of 1000-1500 soldiers surrender after the Last Invasion of Britain.