served as President until 4 March 1797, aged 65 years 10 days (thus becoming the only ex-President)
died 14 December 1799, aged 67 years 295 days,
held the record as longest-lived President for another 3 years, 250 days after his death:
14 years 113 days in total as the longest-lived president.
John Adams, born 20 October 1735 (NS), served as President 4 March 1797 to 4 March 1801.
He outlived Washington on 20 August 1803,
died 4 July 1826, aged 90 years 247 days,
held the record as longest-lived president for another 175 years, 99 days after his death:
198 years 51 days in total as the longest-lived president.
Ronald Reagan, born 6 February 1911, served as President 20 January 1981 to 20 January 1989.
He outlived Adams on 11 October 2001,
died 5 June 2004, aged 93 years, 120 days,
held the record as longest-lived president for another 2 years, 158 days after his death:
5 years 30 days in total as the longest-lived president.
Gerald Ford, born 14 July 1913, served as President 9 August 1974 to 20 January 1977.
He outlived Reagan on 10 November 2006,
died 26 December 2006, aged 93 years, 165 days,
held the record as longest-lived president for another 10 years, 333 days after his death:
11 years 13 days in total as the longest-lived president.
George H.W. Bush, born 12 June 1924, served as President 20 January 1989 to 20 January 1993.
He outlived Ford on 23 November 2017,
died 30 November 2018, aged 94 years, 171 days,
held the record as longest-lived president for another 111 days after his death:
1 year 118 days in total as the longest-lived president.
Jimmy Carter, born 1 October 1924, served as President 20 January 1977 to 20 January 1981.
He has just today outlived Bush.