Fatto generale: 1575 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Fatto matematico: 1575 is the number of partitions of 24.
Trivia: 1575 is a boring number.
Data storica: April 23rd is the day in 1955 that the Canadian Labour Congress is formed by the merger of the Trades and Labour Congress of Canada and the Canadian Congress of Labour.