Fatto matematico: 9427 is the smallest number that can not be formed using the digit 1 at most 29 times, together with the symbols +, –, × and ÷.
Trivia: 9427 is an uninteresting number.
Data storica: October 22nd is the day in 1910 that Dr. Crippen is convicted at the Old Bailey of poisoning his wife and is subsequently hanged at Pentonville Prison in London.