Fatto matematico: 7187 is the smallest number that can not be formed using the digits 0-8 at most once, together with the symbols +, –, × and ÷.
Trivia: 7187 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Data storica: September 4th is the day in 626 that Li Shimin, posthumously known as Emperor Taizong of Tang, assumes the throne over the Tang Dynasty of China.