apparently 54,000. Seems like it is including even fictional words though in this test (like from fiction novels). Ironically I scored higher on the expert words (18/20) than the "advanced" words (11/20)
The word was "Brobdingnagian", which apparently means "giant", from the book, Brobdingnag, published in the 1700s. I know all of the words you listed, even if I don't know t he books they came from, on the other hand, I've never heard anyone use "Brobdingnagian" and I've never heard of the book it came from either.
quixotic, scrooge, shangri-la, Uncle Tom, gargantuan, kafkaesque, blurb, milquetoast
and words like cyberspace were first used in fiction
once real people use them, they stop being fictional words