general_fact: 7851 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 7851 is an uninteresting number.
trivia: 7851 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
historical_date: June 29th is the day in 1922 that France grants 1 km² at Vimy Ridge "freely, and for all time, to the Government of Canada, the free use of the land exempt from all taxes".