God is claimed to be immaterial. This means he is not made of atoms because atoms are material.

If God is composed of atoms, like you seem to believe, then he would have a location in space and time. From there, he would have to get to a person praying to answer their prayer. If he is physical, he must travel. Does he bounce all over the world every day tens of thousands of times? This is beyond impractical--it is impossible. This cannot be God.