Goddamn assembly...

For an assignment, I need to use MIPS to create a program that will check a number to see if it's a perfect number (All factors add up to the number.)  I have no freaking clue how to go about doing this.  It seems like I'd have to have it check every number before it to see if it's a factor, then add them all up to check to see if they work.  This seems kinda insane since it's more of a beginner class...

How would I go about even beginning something like this?  Is there any easier way to do it?

you only have to check each number up to and including the square root of, every factor (save the root itself) thus determined will have a corresponding factor which can be worked out by simple division.