As of 2021 the U.S. currently retains the highest GDP on Earth:
Nominal GDP Rankings by Country
What are the largest economies in the world? According to the International Monetary Fund, these are the highest ranking countries in the world in nominal GDP:
United States (GDP: 20.49 trillion)
China (GDP: 13.4 trillion)
Japan: (GDP: 4.97 trillion)
Germany: (GDP: 4.00 trillion)
United Kingdom: (GDP: 2.83 trillion)
France: (GDP: 2.78 trillion)
India: (GDP: 2.72 trillion)
Italy: (GDP: 2.07 trillion)
Brazil: (GDP: 1.87 trillion)
Canada: (GDP: 1.71 trillion)
The Largest Economies in the World
The three largest economies in the world as measured by nominal GDP are the United States, China, and Japan. Economic growth and prosperity are impacted by a wide array of factors, namely investment in workforce education, production output (as determined by investment in physical capital), natural resources, and entrepreneurship. The economies of the U.S., China, and Japan all have a unique combination of these factors that have led to economic growth over time, as outlined below."
In terms of U.S. currency: Standing on Its Own as the World’s Reserve Currency
As a result of the Bretton Woods Agreement, the U.S dollar was officially crowned the world’s reserve currency and was backed by the world’s largest gold reserves. Instead of gold reserves, other countries accumulated reserves of U.S. dollars.
https://www.investopedia.com/articl...-us-dollar-became-worlds-reserve-currency.asp
https://worldpopulationreview.com/countries/countries-by-gdp