Frank Jacobs asks:

What if the world were rearranged so that the inhabitants of the country with the largest population would move to the country with the largest area? And the second-largest population would migrate to the second-largest country, and so on?

The US stays in place:

Strangely enough, the US itself would not have to swap its population with another country. With 310 million inhabitants, it is the third most populous nation in the world. And with an area of just over 3.7 million mi² (slightly more than 9.6 million km²), it is also the world's third largest country (2). Brazil, at number five in both lists, is in the same situation. Other non-movers are Yemen and Ireland. Every other country moves house.

(Hat tip: Compass)