This witty introduction to number theory deals with the properties of numbers and numbers as abstract concepts. Topics include primes, divisibility, quadratic forms, related theorems, explored in imaginative chapters such as "Seven jogged my elbow," "On a clear day you can count forever," and "When the clock strikes thirteen."
Here's a sample of other books in this Dover category
Recreations in the Theory of Numbers by Albert H. Beiler Number theory proves to be a virtually inexhaustible source of intriguing puzzle problems. Includes divisors, perfect numbers, the congruences of Gauss, scales of notation, the Pell equation, more. Solutions to all problems.
Number Theory and Its History by Oystein Ore Unusually clear, accessible introduction covers counting, properties of numbers, prime numbers, Aliquot parts, Diophantine problems, congruences, much more. Bibliography.
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.
The Number System by H. A. Thurston This book explores arithmetic's underlying concepts and their logical development, in addition to a detailed, systematic construction of the number systems of rational, real, and complex numbers. 1956 edition.
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.
Science and Method by Henri Poincaré Classic account of basic methodology and psychology of scientific discovery explains how scientists analyze and choose their working facts and explores the nature of experimentation, theory, and the mind. 1914 edition.
Elementary Number Theory: Second Edition by Underwood Dudley Written in a lively, engaging style by the author of popular mathematics books, this volume features nearly 1,000 imaginative exercises and problems. Some solutions included. 1978 edition.