It's 'obscure' in the sense that something like To Kill a Mockingbird is 'obscure' (The only reason I know it is due to the prevalence of US pop-culture and it being referenced there). Sure everybody in the US probably knows about it and many read it in school, but outside of the US it's pretty rare to meet someone who has read it. I'd be willing to bet a lot more people in Europe have read The Master and Maragrita than To Kill a Mockingbird for example.
Agreed. It comes up a million times on HN and has an enormous amount of ratings on Goodreads, #3 in Russian lit behind only 1 book of Tolstoy and Dostoevsky: https://www.goodreads.com/book/show/117833.The_Master_and_Ma.... It is widely popular in the English-speaking world; not obscure.