An Illustrated Theory of Numbers (2017)
I hope you enjoy the book -- the AMS sale does give a great price!  Part of the reason I went with the AMS was that they're a nonprofit and their prices are reasonable for a hardcover book printed (offset, not digital on-demand) in color.As the author, I'll add a few remarks and answer some questions about the book.1.  I made a book webpage at illustratedtheoryofnumbers.com.  The errata are there.  Also you can find a series of programming tutorials, if you wish to learn number theory with Python.  I go from programming basics to primality-testing, RSA, etc.2.  I didn't provide solutions in the book.  :(  But there's always online discussion boards.  Someday I'll write many more exercises and provide some solutions.3.  It's been used as a textbook for undergraduate number theory, e.g. at Rice, UC San Diego, next semester at Georgia Tech I think, etc.4.  No full e-book version is planned.  It's all very old-fashioned, but I spent a lot of time on page layout, optimizing for print, etc.5.  I took a stronger stance on zero being a natural number in an early draft.  Now I just try to make it clear that it's the convention I choose.  If it's good for Bourbaki, it's good for me.Feel free to drop a note if you have more questions about the book.  My email is not hard to find.Happy holidays!
Marty Weissman