You don't understand why a sequence of 39 digits might be harder to memorise than sequences of 10? 16 is longest of the examples that people actually memorise (no, people are not memorising their bitlocker keys), and even then they have 1 example that lasts at least 5 years to deal with, instead of however many IP addresses they have to deal with.

Also many of my account numbers and my nations equivalent of a SSN are alphanumeric so 36 vs 16 choices.