Yes, this is true. The most popular, given, and common name in the world is Muhammad, according to the Columbia Encyclopedia (2000, 6th edition). There are approximately 150 million men (and boys) who have their name Muhammad.
In the United States, the name got ranked 4,194 out of 88,799 in the 1990 census for people of all ages. In 2006, 639th popular first name for newborns was Muhammad according to the Social Security Administration. Mohammad and Mohammed are ranked 589th and 633rd, respectively. Mohamed was also the 430th most common spelling variant in the US for the year of 2009.
In 2007, the second most popular given name in Britain was Muhammad, including 14 variations in its spelling, reported by the BBC. Mohammed was the 16th most popular baby name in 2009 in England and Wales (most popular in the West Midlands).
Statistics says that 8,928 Danish Muslims have their name Muhammad and it was reported that 167 new born babies were registered in 2004 only. Some men who have name of Muhammad use their middle name because they think it’s too common.