"There we go. My tweet has been posted. That's what I'm talking about," said President Barack Obama.
The next four most followed leaders were Pope Francis, who has accounts in various languages, then Prime Minister Modi of India, President Erdogan of Turkey and the White House.
Pope Francis averaged almost 10,000 retweets per tweet on his Spanish account and about 7,500 retweets on his English account. Obama wasn't close to that, averaging only 1,210 retweets for fourth place, behind King Salman of Saudi Arabia and President Maduro of Venezuela.
The most popular Twitter accounts aren't necessarily the most likely to interact with others.
The leaders who reply to tweets most often were Rwanda's President, whose tweets are about 86 percent replies. Next were the Prime Minister of Norway with 73 percent, the President of Ecuador with 71 percent, the Foreign Minister of Rwanda with 70 percent and the Foreign Minister of Kuwait with 68 percent.
Obama's reply rate is effectively 0 percent.
But, as the study notes, very few world leaders are actually tweeting. Typically, that task falls to their staff.
The 'Twiplomacy' study was conducted by public relations firm Burson-Marsteller. Music by Planet Boelex & Mosaik / CC BY NC ND 3.0.