Bitcoin difficulty is not measured in bits but its own unit (some hashrate was defined as difficulty 1, and difficulty 10 means the hash rate is 10x that). The

Bitcoin difficulty is not measured in bits but its own unit (some hashrate was defined as difficulty 1, and difficulty 10 means the hash rate is 10x that). The number you see on that website is also in trillions, so the current difficulty is about 50 trillion. Also, you get more than one Bitcoin per hash (currently 6.25, halving every few years). To mine six BTC, you currently need almost 80 bits of zeroes, so 28 bits is basically trivial.