We determine invariants like the Smith normal form and the determinant for certain integral matrices which arise from the character tables of the symmetric groups Sn and their double covers. In particular, we give a simple computation, based on the theory of Hall-Littlewood symmetric functions, of the determinant of the regular character table ?RC of Sn with respect to an integer r? 2. This result had earlier been proved by Olsson in a longer and more indirect manner. As a consequence, we obtain a new proof of the Mathas' Conjecture on the determinant of the Cartan matrix of the Iwahori-Hecke algebra. When r is prime we determine the Smith normal form of ?RC. Taking r large yields the Smith normal form of the full character table of Sn. Analogous results are then given for spin characters.