What were the principal strengths and constraints of the Aztec economy?

The Aztecs weaknesses included numerous enemies from a long past, in comparison to the Spanish they lacked technology, they often fell prey to simple diseases, their religion made them weaker and caused them to lose numbers due to human sacrifices. Their strengths included a very high population, they were incredibly familiar with their land due to extensive travel and study of their region, they had conquered numerous cultures and learned lots of things from those they conquered, they had a very strong economy and grew many of their own crops reducing the need to trade with other empires, and they were incredibly intelligent even teaching their children math and science.