Hecho general: 431 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Hecho matemático: 431 is the index of a prime Fibonacci number.
Trivia: 431 is a boring number.
Fecha histórica: March 6th is the day in 12 BC that the Roman Emperor Augustus is named Pontifex Maximus, incorporating the position into that of the Emperor.