- The total number of digits in the binary representation is somewhere between 32 and 128.
I like using the standard library `secrets` module.
>>> import secrets
>>> secrets.randbelow(1<<128)
8080125189471896523368405732926911908
If you want an easy-to-follow rule, just use the above snippet to get a 128-bit number. More than 128 bits won't do you any good (at least by default, the internal bottleneck inside of SeedSequence is a 128-bit pool), and 128-bit numbers are just about small enough to copy-paste comfortably.