I am trying to write out the Hecke Operator; however, I don't know how to sum over all divisors of an integer. Could someone please give me some advice how to do that. Below is the Hecke Operator definition I use:
$$T_NZ(\tau)= \sum_{d|N}\sum_{\kappa=0}^{d-1}Z\left(\frac{N\tau/d +\kappa}{d}\right)$$
Many thanks!!
Sum[f[d], {d, Divisors[122]]
$\endgroup$