Fatto matematico: 9643 is the smallest number that can not be formed using the numbers 2^{0}, 2^{1}, ... , 2^{7}, together with the symbols +, –, × and ÷.
Trivia: 9643 is an uninteresting number.
Data storica: May 26th is the day in 1879 that Russia and the United Kingdom sign the Treaty of Gandamak establishing an Afghan state.