what do you mean by boxed?
if i can remember correclty i think the highest value that can be stored in an 32 bit integer is 2^32 - 1(i think) so in base 10 the highest number would be 4,294,967,295 and thats for unsigned (i think). For the value type thing i think this site found through google might explain a bit about it.
http://www1.cs.columbia.edu/~lok/csh...pes/Int32.html