Number theory proves to be a virtually inexhaustible source of intriguing puzzle problems — interesting to beginning and advanced readers. Divisors, perfect numbers, the congruences of Gauss, scales of notation, the Pell equation, many other aspects produce ingenious puzzles. Solutions to all problems.
Here's a sample of other books in this Dover category
An Adventurer’s Guide to Number Theory by Richard Friedberg This witty introduction to number theory deals with the properties of numbers and numbers as abstract concepts. Topics include primes, divisibility, quadratic forms, and related theorems.
Elementary Theory of Numbers by William J. LeVeque Superb introduction to Euclidean algorithm and its consequences, congruences, continued fractions, powers of an integer modulo m, Gaussian integers, Diophantine equations, more. Problems, with answers. Bibliography.
Elementary Number Theory: An Algebraic Approach by Ethan D. Bolker This text uses the concepts usually taught in the first semester of a modern abstract algebra course to illuminate classical number theory: theorems on primitive roots, quadratic Diophantine equations, and more.
The Theory of Remainders by Andrea Rothbart An imaginative introduction to number theory and abstract algebra, this unique approach employs a pair of fictional characters whose dialogues explain theories and demonstrate applications in terms of football scoring, chess moves, and more.
