The EU is 66% bigger (in population) than US, 500 vs 300 million.
Even just rhe Eurozone, 328 million, is 9-10% bigger in population than the US.
Yet crucial difference in the socio-economic systemics and the "power" of the US economy in the world is, IMO, that the US has a well functioning Internal Market, in spite of the efforts of 17 years in the EU for the creation of a single market for capital, goods, services and, yes, jobs.
That is one of the reasons a "deeper" EU is IMO needed in order to raise the collective power of the EU members and citizens in a volatile world.
Read more on this in future posts.