That's according to social media aggregator Klout
Klout adds together tweets, Facebook likes, pings, mentions on Google, status updates and other social media activity and to give a score out of 100, depending on how often what someone has said gets repeated by others online.
The website has been labelled by technology pundits as one to watch in 2011 and has recently been hired by Disney to carry out research on its behalf.
Bieber has the maximum score of 100, with his tweets being retweeted on average five million times each. Barack Obama scores 88, with his tweets being repeated just 250,000 times on average.
Speaking to the Guardian, Klout founder Jose Fernandez said that Klout’s calculations were “…the opposite of advertising.” He also said “For some things it’s reaching the few that matter. If you say you like something, how many people and who does that affect? We are living in an attention economy. We have too much information coming at us. Who do we trust, whose links are we going to click?”