Hecho matemático: 9805 is the number of subsequences of {1,2,3,...15} in which every odd number has an even neighbor.
Trivia: 9805 is an unremarkable number.
Fecha histórica: November 4th is the day in 1852 that Count Camillo Benso di Cavour becomes the prime minister of Piedmont-Sardinia, which soon expands to become Italy.