Don't see the point of putting an arbitrary number like 500, but many systems do that in their training, Ip training fro example.
Doing 500 push-ups ALL day is not that whack, I mean, if you are awake for the typical 16 hours, from 6 to 10 for example, that is 32 per hour.
Typically you do the harder ones first and finish off with the easy ones.
EX:
If you are doing knuckle, 5 finger, two finger and phoenix-eye fist push-ups you would do as many PE fist ones, rest 30 -60 sec, do as many 2 finger, rest, do as many 5 finger, rest and do as many knuckle ones and you are done.
Repeat every hour if you can.
I wouldn't do it everyday mind you, your body need recovery time, especially your joints.
Psalms 144:1
Praise be my Lord my Rock,
He trains my hands for war, my fingers for battle !