1. You need to know the rms power rating on each woofer and the impedance. That will tell you how much total power you need. Very often the power rating is exaggerated. If each woofer was actually rated for 2100 watts you would need 8 times that amount of power to play them all at the maximum volume they are capable of producing. I suspect you would not be able to do that with one amp. The power supplied to the amp or amps would have to be quite large too.
2. When you look at power amps you need to know the rms (not peak) power and the minimum impedance it will handle. You will need to connect the woofer in such a way as to present to the amp that impedance. http/physics.bu.edu/py106/notes/Circuits.html