Gerald Ford (38th president ) -- lived the longest (93 years, 165 days)
Second and third in life span were Ronald Reagan -- {93 years, 120 days }
and John Adams -- 90 years plus.
Contenders for the future:
As of June 12, 2011, George Bush (41) is the oldest living ex-President at 87.
As of October 1, 2011, Jimmy Carter (39) will also be 87.