1,000,000 people = 21 BTC -> (every 1 person is 21 BTC)

1 person = 21,000,000 BTC
10 people = 2,100,000 BTC
100 people = 210,000 BTC
1,000 people = 21,000 BTC
10,000 people = 2,100 BTC
100,000 people = 210 BTC
1,000,000 people = 21 BTC
10,000,000 people = 2.1 BTC
100,000,000 people = 0.21 BTC
1,000,000,000 people = 0.021 BTC
10,000,000,000 people = 0.0021 BTC