This paper provides a topological interpretation for number theoretic prope
rties of quantum invariants of 3-manifolds. In particular, it is shown that
the p-adic valuation of the quantum SO(3)-invariant of a 3-manifold M, for
odd primes p, is bounded below by a linear function of the mod p first bet
ti number of M. Sharper bounds using more delicate topological invariants a
re given as well. (C) 2000 Elsevier Science Ltd. All rights reserved.