The presidents' birthdays are listed in the back of the book, "The Lord Needed a Prophet."  Here they are:
 

Joseph Smith, Jr. - Dec. 23, 1805
Brigham Young - June 1, 1801
John Taylor - Nov. 1, 1808
Wilford Woodruff - Mar. 1, 1807
Lorenzo Snow - Apr. 3, 1814
Joseph F. Smith - Nov. 13, 1838
Heber J. Grant - Nov. 22, 1856
George A. Smith - Apr. 4, 1870
David O. McKay - Sep. 8, 1873
Joseph Fielding Smith - July 19, 1876
Harold B. Lee - Mar. 28, 1899
Spencer W. Kimball - Mar. 28, 1895
Ezra Taft Benson - Aug. 4, 1899
Howard W. Hunter - Nov. 14, 1907
Gordon B. Hinkley - Jun. 13, 1910