Justin Bieber’s manager, Scooter Braun, thinks New York might not be the best locale for his high-flying friend, tech billionaire Sean Parker. “New York is the city that never sleeps. I think for a person like Sean, it’s good to be in a city that sleeps,” Braun told Page Six Magazine, out on Thursday. “Sean needs to be focused. He doesn’t need distractions. Sean’s at his best when he can collect his thoughts.” The Napster founder and Spotify backer, who is played by Justin Timberlake in “The Social Network,” doesn’t mind the party-boy reputation he inherited from the film, but his friends say he can’t seem to shake a deep insecurity about the two-dimensional portrayal. “I think he feels like people don’t take him seriously,” Grateful Dead lyricist John Perry Barlow, 64, who befriended Parker during his Napster days, said. “People still think that he just happened to be in the right place at the right time. People often think of him as being like the character . . . in the movie. Which, like any caricature, often fits gross dimensions, but the reality is often more interesting and complicated.” Parker’s pals maintain he’s still the same nerd as before, but they blame the movie for making him so image-conscious.