There are many books that have numbers in their titles, some of which are widely acclaimed classics.
One of the most popular books with a number in the title is Harper Lee's Pulitzer Prize winning novel "To Kill a Mockingbird." As the title indicates, the book is about understanding prejudice and courage in the context of race, identity, and morality.
Another classic is William Golding's "Lord of the Flies," which follows the lives of a group of English schoolboys who are stranded on an island and learn to govern themselves. The title refers to the name given to a large pig's head that serves as an idol to the boys.
Other books with numbers in their titles include Kurt Vonnegut's "Slaughterhouse-Five," which comments on the terror and destruction of World War II; Arthur Koestler's "Darkness at Noon," which looks at the oppressive Stalin regime; and "The Catcher in the Rye" by J.D. Salinger, a story of one teenage's journey of self-discovery.
For a more contemporary choice, the book "The Seven Husbands of Evelyn Hugo," a story of a fictional Hollywood star and her many marriages, has a number in the title and has been highly praised.