The figure comes from CEO Kazuo Hirai, who said that 2.1 million PS4 owners have signed up for the $50 yearly service.
Unlike the PS3 and PS Vita before it, however, the PS4 requires users to sign up for the service in order to play online multiplayer games. A PlayStation Network account is still free for users, however, of which Sony estimates there are 150 million users.
The PS Plus allows for a single PSN account while allowing for subscribers to not only access online multiplayer games but also receive free PS3, PS4 and PS Vita games.
Earlier this week Microsoft announced it would have news soon on a similar free-game program with Xbox Live for the Xbox One called Games with Gold. The Xbox 360 already offers the service for Gold members.