A man with no home and no job, Paul Erdős was the most prolific mathematician who ever lived. Erdős, who died in 1996 at the age of 83, inspired generations of mathematicians throughout the world with his insightful approach and wry humor.

"N is a Number: A Portrait of Paul Erdős" follows him for four years through four countries, presenting his mathematical quest and its personal and philosophical dimensions. Animated sequences illustrate the kinds of mathematical problems that Erdős pursued.