I know that Virtualmin can run with (far) fewer services in 96MB, but 64MB is too tight for pretty much anything except very basic Apache (and no management tools). You'll need plenty of swap space, in either case (and time to wait on things to swap in and out while working).
There is a guide for running Virtualmin on low memory systems, and it's possible to get a pretty full-featured system except AV/spam scanning (which are hugely resource intensive) into 128MB.
http://www.virtualmin.com/documentation/id,virtualmin_on_low_memory_systems/