General fact: 1559 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 1559 is the smallest prime p with 16 consecutive quadratic residues mod p.
Trivia: 1559 is an unremarkable number.
Historical date: April 7th is the day in 1994 that Auburn Calloway attempts to hijack FedEx Express Flight 705 and crash it to insure his family with his life insurance policy.