I nominate 60. Babylonian mathematics was sexagesimal (base 60) which is a superior mathematical system to base 10. The number 60, a superior highly composite number, has twelve factors: 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, and 60, of which 2, 3, and 5 are prime numbers. With so many factors, many common mathematical operations are much simpler than in base 10. Base 10 has no special mathematical properties apart from as an accident of evolution, we primates ended up with 10 fingers.
We still have some vestiges of the babylonian system however, 60 minutes in an hour. 360 (6 sixties) degrees in a circle.
It is another accident of evolution that we ended up with 12 finger joints, allowing one to count to twelve with a single hand by tapping the thumb on each finger segment in turn.
Most of your argument seems to stand for 30 instead of 60: 2 x 3 x 5 = 30, which is a smaller number with mostly the same properties as 60.
If you want more divisibility (into quarters, eigths, ninths...), you can continue multiplying further, but 60 is as much a "historical accident" as 10 is an "accident of evolution".
30 has divisors 1, 2, 3, 5, 6, 10, 15, 30 - eight divisors. But 24 is lower and also has eight (1, 2, 3, 4, 6, 8, 12, 24), making 30 less 'special'.
60 is the lowest highly composite number with 5 (and therefore 10) as a factor, which makes it a strong attractor when choosing bases for measuring systems.
Sure, but caring about 5 (and 10) is not what the GP comment stressed (actually, quite the opposite). If we do care about 10, then 60 is indeed appealing, but also an argument for base 10 too — which they argued against.
"Highly composite" number being used as a base for a numbering system does not really strike me as non-arbitrary either.
Choosing 60 and saying it makes more sense than, say, 2520 (which is also highly composite, but divisible by 1-10 too) is pretty arbitrary imho. Yes, my "criteria" is similarly arbitrary but focused on "10 does matter" ("I want to easily divide this into 2-10 groups"): both are too large to have individual names for each digit in a supposed number system with base 60 or 2520.
We still have some vestiges of the babylonian system however, 60 minutes in an hour. 360 (6 sixties) degrees in a circle.