As of December 6th, there are A LOT of PS4 consoles in the wild.
The report comes from Takashi Mochizuki, Wall Street Journal technology reporter in Tokyo:
Sony: have sold 50 million units of PlayStation 4 as of Dec. 6. The past black Friday week was the best period ever for the console.
— Takashi Mochizuki (@6d6f636869) December 7, 2016
It was confirmed by Sony Interactive Entertainment itself. PlayStation 4 is available in 122 countries and regions. PS4 Pro sales are included in those 50 million units.
PlayStation 4 originally launched on November 15, 2013 in North America and came to Europe two weeks later. Both PS4 Slim (with small hardware revisions) and PS4 Pro (4K support, upgraded GPU, higher CPU clock, but with no Ultra HD Blu-ray support) released this year.