Can determiners precede pronouns?

Generally, determiners are defined as preceding nouns, but can they also precede pronouns? For example, the word "least" can take a number of forms including adverb, adjective, determiner, AND pronoun, as in "that’s the least of my problems" or "he earns the least". These examples are used to illustrate the usage of "least" as a pronoun. But isn’t it actually a "noun" in these contexts? Then it would make sense for a determiner to precede it.