general_fact: 28373 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 28373 is an unremarkable number.
trivia: 28373 is an unremarkable number.
historical_date: September 5th is the day in 1862 that James Glaisher, pioneering meteorologist and Henry Tracey Coxwell break world record for altitude whilst collecting data in their balloon.