RSA numerical questions Let $n$ be the modular arithmetic, $p$ and $q$ the two large primes such that $n=p*q$ and $e$ the public exponent. Here they are two "simple" numerical questions:


If $p = 13$ and $q = 17$, what is the range for exponent e?
Let be $p = 7$, $q = 11$ and $e = 3$. What is the max integer that can be encrypted?


About 1), I know that $e$ needs to be relatively prime to $φ(n)=(p-1)*(q-1)$, but how can I determine the range? 

About 2), is there really a threshold on the maximum integer I can encrypt with RSA?
what is the range for exponent e?


Actually, there is no required upper bound for $e$ (except that some implementations may reject ridiculously large values).  The math behind RSA states that any $e$ that is relatively prime to both $p-1$ and $q-1$ will work, no matter how large it is. There might not appear to be a need for an $e &gt; lcm(p-1, q-1)$ (as for any such $e$ larger than that, there is a smaller $e$ that acts equivalently). However, there are obscure cases where such $e$ arise; one possibility is some shared computation of the RSA key pair (where no one entity knows the factorization) could possibly generate such a huge $e$ (depending on how that shared computation works).


  What is the max integer that can be encrypted?


Well, if you omit the padding, the largest value that can be encrypted is $N-1$, as Raoul722 states.  However, it is rarely a good idea to omit the padding in RSA (and if you have to ask, you don't know enough to safely omit it).