That must be pretty well known because I'm not interested in that but even I know the name.
It must be pretty famous because I don't pay any attention to things like that but I do know the name.
1) That must be pretty well-known because I'm not interested in that but even I know the name.
「興味のない私でも名前を知ってるくらいだからかなり有名に違いない。」
well-known で「有名な・よく知られた」
2) It must be pretty famous because I don't pay any attention to things like that but I do know the name.
「そんなのに見向きもしない私でも知っているくらいだから、よっぽど有名なんだろうね。」
famous で「有名な」
pay attention で「注意を注ぐ・気にとめる」
ご参考になれば幸いです！
日本 
