Coefficients of modular forms modulo (powers of) primes

In this talk, we will try to discuss some properties of the coefficients of classical modular forms modulo primes or prime powers. The talk will be divided into two parts. The first part will be concerned with holomorphic modular forms, particularly weight 2 newforms, and discuss partly on a joint work with Tian Wang on their ordinary primes. The second part will be concerned with meromorphic modular forms (of level 1), and discuss some numerical congruences satisfied by their coefficients.