Libgober and Wood proved that
the Chern number c1cn−1 of a compact complex manifold of dimension n can
be determined by its Hirzebruch χy-genus. Inspired by the idea of their
proof, we show that, for compact, spin, almost-complex manifolds, more
Chern numbers can be determined by the indices of some twisted Dirac and
signature operators. As a byproduct, we get a divisibility result of certain
characteristic number for such manifolds. Using our method, we give a direct
proof of the result of Libgober and Wood, which was originally proved by
induction.