You must take a look at the following thoroughly list for Mathematical fiction http://kasmana.people.cofc.edu/MATHFICT/all.php
Finally, let me just mention a recent novel about Hardy, Ramanujan, Littlewood, etc. The title is "The Indian Clerk: A Novel" and the author is "David Leavitt" .http://www.amazon.com/The-Indian-Clerk-A-Novel/dp/1596910402