Daniel Charles Shanks (January 17, 1917 – September 6, 1996) was an American mathematician who worked primarily in numerical analysis and number theory.

Prior to obtaining his PhD, Shanks worked at the Aberdeen Proving Ground and the Naval Ordnance Laboratory, first as a physicist and then as a mathematician.

He spent one year at the National Bureau of Standards before moving to the University of Maryland as an adjunct professor.

[1]: 813 Shanks wrote the book Solved and Unsolved Problems in Number Theory,[3] which mostly depended on quadratic residues and Pell's equation.

Writing about the possible non-existence of odd perfect numbers, which had been checked to 1050, he famously remarked that "1050 is a long way from infinity.