Who is the youngest president of the united states?

Two measures of the longevity are given - this is to allow for the differing number of leap days occurring within the life of each President. The first column is the number of days between date of birth and date of death, allowing for leap days; the second column breaks this number down into years and days, with the years being the number of whole years the President lived, and the days being the remaining number of days after his last birthday.