And of all those people, only one is another world leader.
No, it's not U.S. President Barack Obama. Nor is it British Prime Minister David Cameron. And it's not even Israeli Prime Minister Benjamin Netanyahu, despite the support that Ottawa gives him in foreign relations.
The latter two, and many other world leaders, follow @pmharper, but Mr. Harper doesn't follow them back.
He does, however, follow Russian prime minister (and ex-president) Dmitry Medvedev.
Mr. Medvedev is one of the best-connected world leaders on Twitter, according to the social media study Twiplomacy from communications firm Burson-Marsteller.
The Russian PM is also one of the only accounts mutually followed by both the White House (the official presidential account) and Barack Obama's campaign.
And unlike most political accounts that are handled by staff (including Mr. Harper's), Mr. Medvedev appears to be personally active on his. He's well known as an amateur photographer and Instragram fan. You'd have a hard time distinguishing his artful photos from a hip Canadian with an iPhone.
Mr. Harper joined Twitter in July, 2007, making him one of the first world leaders on the social media platform. But he didn't send a tweet until more than a year later, which promoted a new Conservative Party website. His account has been silent since congratulating Olympic medal winners last month.
So who really has the most influence in the Twitterverse? Mr. Harper does have a higher Klout score.