The United States is considered the number one economy in the world due to its high GDP, strong industrial base, technological advancements, and global influence. It has a diverse range of industries such as finance, technology, manufacturing, and services, which contribute significantly to its economic growth. The United States also has a large consumer market and is home to many multinational corporations. Additionally, its currency, the US dollar, is widely accepted and used for international trade, further solidifying its position as the top economy globally.