Dive into the fascinating world of number theory with this concise exploration of 45 essential concepts, each explained in just 7 minutes. Perfect for enthusiasts and newcomers alike, the book covers everything from prime and composite numbers to the intricacies of cryptography and the mysteries of perfect numbers. Unravel key principles like the Fundamental Theorem of Arithmetic, modular arithmetic, and the Goldbach Conjecture, while discovering their applications in computer science and beyond. With a focus on clear explanations and engaging insights, this guide makes complex ideas accessible, sparking curiosity and a deeper appreciation for the beauty of numbers.