understanding bits and difficulty in a block header
This block:
https://blockchain.info/block/00000000000000000025c089d0a7b2bf6241888c4dd90ab7a4c4baa6a2823551
Shows difficulty at 3,007,383,866,429.73, and bits at 392009692.
If I want to see how many zeros need to be in the hash, I believe I can just do:
(log2(3007383866429.73) + 32) / 4) => 18.362911541451258
Which is correct.. But how does bits come from difficulty? How can I calculate the number of zeros from the bits instead of the difficulty?