Yes but it's a bitch to program, multiple memory hierarchies and address spaces (at least 3), only one index register (hard to move stuff), and enough variants that "8051" is more of a species definition than of a particular architecture
(disclaimer: I sell an 8051 based product, have sold them in the past - never again)
(disclaimer: I sell an 8051 based product, have sold them in the past - never again)