A number-theoretic approach to homotopy exponents of SU(n) Donald M. Davis and Zhi-Wei Sun dmd1@lehigh.edu zwsun@nju.edu.cn Lehigh University, Bethlehem, Pa, 18015 Nanjing University, Nanjing 210093, PRC AMS Classifications: 55Q52, 57T20, 11A07, 11B65, 11S05 Abstract: We use methods of combinatorial number theory to prove that, for all n and p, some homotopy group pi_i(SU(n)) contains an element of order p^{n-1+ord_p([n/p]!)}, where ord_p(m) denotes the exponent of p in m.