The e stands for 10^x, which means that 2e-104 is 2 * 10^-104.

If you want to get results that have an e-value of below 10^-5, the easiest solution is to set the evalue parameter in your BLAST search to 1e-5 or 0.00001.

In case you already have your result file and can not resubmit your query, most scripting languages allow a float(..) conversion of scientific notation, You could also use a regex to search for that which would be ([0-9]+e-[6-9][0-9]*)|(1[.0]*e-5)