Fatto matematico: 1664 is a value of n so that n(n+9) is a palindrome.
Trivia: 1664 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 1972 that Bloody Friday bombings by the Provisional IRA around Belfast, Northern Ireland – 22 bombs are detonated, killing 9 and seriously injuring 130.