How many Soviet republics were there?

Based on what you said, Alexey, it can be assumed that you created this topic only to find out how many people lived in the Soviet Union, because the number of "mental perceptions" equals the number of people living in that territory. Regarding the socio-economic and political formation. I suggest creating a topic where we can discuss (based on facts, our personal opinion, and the opinions of other people) what the USSR was, as an economic formation (was it communism, socialism, or perhaps state capitalism?). Was the USSR a totalitarian or democratic country? Or maybe authoritarian? Were the principles of natural law observed? Was it a monarchy or a republic? And so on.