I should email him and ask if three days a week is infrequent enough to avoid burnout. That’s pretty often to maintain such an incredible level of quality. (Tom Scott had enough after 10 years.) But maybe since it’s his full-time gig, it’s optimal - he can spend most of the week reading cool stuff that gives him tons of good ideas and he actually wouldn’t want to publish any less frequently.
In several European languages like French and Danish, 20 is used as a base, at least with respect to the linguistic structure of the names of certain numbers (though a thoroughgoing consistent vigesimal system, based on the powers 20, 400, 8000 etc., is not generally used).
"Eighty-seven" in English is "quatre-vingt sept" in French; "four twenties seven", which is basically what he's saying.
The second one is arguably not vigesimal but instead just an echo of the Germanic way of saying numbers that English has all but lost. You'd be surprised how long things will lurk around the fringes of a language despite not being the most popular way of saying things.