That's 720,000 hours per day. If you figure people work 8-hour days, that's 90,000 people. Assuming they never take vacations, don't get weekends off, and really do work 8-hour shifts with no breaks. None of which seems remotely plausible. If we assume 5-day workweeks, 6 hours of actual "productive" time per day, and 2 weeks annual vacation, closer to 175,000 people.
YouTube revenue in the corresponding timeframe is somewhere between $9.5 billion and $14 billion. How much of that is profit and how much is already being spent on infrastructure costs and whatnot is unclear. But 175k people at $50k/year, say, is $8.75 billion/year. Which is getting pretty darn close to those total revenue numbers.
Note that that's $50k expense to the employer (i.e. including benefits, employer-side taxes, office space, etc, etc, not just salaries), which is likely to be an underestimate if these people are in the US.
There's the question of whether every minute of video needs to be watched by humans, of course. But at that point we're back into automation-land to some extent.