In 1842, the Presidential salute was formally established at 21 guns. In 1890, regulations designated the "national salute" as 21 guns and redesignated the traditional Independence Day salute, the "Salute to the Union," equal to the number of states. Fifty guns are also fired on all military installations equipped to do so at the close of the day of the funeral of a President, ex-President, or President-elect.
Dang, I wish I knew that. I would have zoomed up to the army barracks here in Hawaii.