Fatto generale: 387 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 387 is the smallest number with sort-then-add persistence of 10.
Trivia: 387 is an unremarkable number.
Data storica: January 21st is the day in 1789 that the first American novel, The Power of Sympathy or the Triumph of Nature Founded in Truth, is printed in Boston, Massachusetts.