$$e=\lim_{n\to\infty}\sqrt[p_n]{\prod_{k=1}^np_n}$$
as seen at [Gaussianos][1]

$(\prod_{k=1}^np_n=p_n$\# which is the [primorial][2] of the nth prime number $p_n)$


  [1]: http://gaussianos.com/%25C2%25BFque-tiene-que-ver-el-numero-e-con-los-numeros-primos/%20%22Gaussianos%22
  [2]: http://en.wikipedia.org/wiki/Primorial%20%22primorial%22