A common criticism amongst many reviewers was that in spite of its title, no connection is made between Fermat's Last Theorem and the alien invasion. Alex Kasman at "Mathematical Fiction" complained about errors in some of the author's descriptions of the mathematical problems, and in particular their unfair treatment of Wiles's proof of Fermat's Last Theorem. Some reviewers felt that the characters had not been developed sufficiently. Michael Sims of "The Washington Post" said that "these characters are so thin you can see through them." The aliens are depicted as cartoon-like figures, and Ranjit does not appear to be affected by his lengthy incarceration, interrogation and torture. Some critics also felt that the book ended "somewhat precipitously", that after the aliens arrived, the crisis was resolved too quickly, giving the impression "that there was at least a good, long chapter missing."