I don’t know the exact number, but it’ll be pretty close. Obviously you want to get as many of the rewards as possible excluding maps and souls if you so choose. Everything else is very useful. 16 million is how much it costs to complete all of the tasks weekly. So you can take some of that amount off for souls and maps if you don’t want them, then divide by 30. So yeah I’d say at least that much. I did the math and for 16 million gold, all players would have to donate 535k weekly. So I doubt that’s happening.
That’s where the importance of reqs is though, it’s going to be tough for most people to hit those numbers every single week if you want them.