As I am currently working my way through the exercises in Apostol’s book “Introduction to Analytic Number Theory”. Since I wasn’t able to find solutions to all exercises and since the book does not contain solutions, I googled for them.
And then I found this: https://gregoryhurst.com/solutions/. A PDF file containing solutions to most if not all exercises in the book.
😳
Since graduating, I decided to work out all solutions to keep my mind sharp and act as a refresher.
Greg Hurst, author of the solutions, in its preface
I was very happy to have found this work and I am very thankful to its author!