How many YouTube channels are there?

"YouTube has over a billion users — almost one-third of all people on the Internet — and every day people watch hundreds of millions of hours on YouTube and generate billions of views." As for active channels who knows, but they also claim "300 hours of video gets uploaded every minute" so there's that.
Here's my unhelpful response:

An ABSOLUTE MAMMOTH amount, just thinking about the amount of video content that is uploaded every minute would make you dizzy.

Barely helpful response:

If you've already googled it then you probably know, but there is over 2000 channels with over 1mil subscriber.

Untrustworthy source response: seem to think its about 505,347,842. Maybe I'm miss-quoting.
According to social blade there's about 2 million channels with subscribers over 500. Some may be inactive or semi active, some might also be extensions of proper tv channels, etc. so maybe just say there's about 2 million out there with any kind of impact at all