Only in the US. Internationally, the most common last name is Wang:

Wang is a patronymic (ancestral) name that means “king” in Mandarin, and it’s shared by more than 92 million people in China, making it the most popular last name in the world. The reason it’s so populous today may have a lot to do with the fact that many royal families changed their name to Wang when their kingdoms fell under the first Qin dynasty emperor. This was both to preserve their status and protect themselves from assassination.
Source

So Mohammed Wang is the most common name in the world.

It's Wang. There are 92 million people with that surname in China, and a few more in other countries.