University of Michigan also has 50,000 undergraduates drawn from a state with about 10 million population. Since California has about four times the population, that would mean that the UC equivalent in terms of undergraduate student population (about 200,000) is all of the UCs except UCR and UCM.
Even if we consider only the in-state undergraduates, University of Michigan enrollment relative to the state population would probably be equivalent to about four of the larger UC campuses relative to the state population.