For "bigger" devices, it's usually a Cortex inside a system-on-chip or system-on-module, 32 bits single core and a few Mb of RAM for low-end (enough to run regular Linux distro instead of uClinux for instance), 64 bits multicore for high-end devices that deal with audio/video. That kind of business is often resource-hungry in every way.

I work with that kind of stuff, and to me these "microcontrollers" are just monsters that I hesitate to call "micro" when some of my coworkers work on much smaller chips with only a few K of RAM available.