Fatto generale: 19603 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 19603 is an uninteresting number.
Trivia: 19603 is an unremarkable number.
Data storica: September 1st is the day in 1939 that Adolf Hitler signs an order to begin the systematic euthanasia of mentally ill and disabled people.