The Man Who Loved Only Numbers: The Story of Paul Erdős and the Search for Mathematical Truth
Not the story of Ramanujan? No, it's a book about Erdos. What's your point?
No, but they certainly shared a love of numbers. In fact, SrinivasaRamanujan's history and his intersection with Erdos is discussed in pp. 82-91 of this book.
See PaulErdos