general_fact: 20729 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
math_fact: 20729 is a boring number.
trivia: 20729 is an unremarkable number.
historical_date: October 1st is the day in 1905 that František Pavlík is killed in a demonstration in Prague, inspiring Leoš Janáček to the piano composition 1.