Can anyone recommend any accessible number theory books? thanks
If you are looking for an undergraduate text in number theory, you can try looking at this page:
Math 3320 Fall 2008
Download the course notes (chapters 0 to 3). Topics covered include quadratic forms, Diophantine equations, complex numbers, finding rational/integer points in geometric structures such as circles or hyperbolas, topographs, and so forth.
I found these very helpful also when studying number theory:
Lecture Notes
Elementary Number Theory
The IMO Compendium
Hope this helps!
You can also search on google and get free books in number theory in djvu format. If you are looking for books in algebaric number theory then there are two good book, I can recommend.
Algebraic number theory by Ian Stewart, and Tall.
Introductory algebraic number theory by Saban Alaca, and Kenneth S. Williams.