Your s(n) def works wrong. For example try 4 or 16
You should add something like "if (i*i == n): S += i"

Do not brute force the sum of divisors. Use math to reduce iteration while finding the sum of divisors

Seems so. But the problem is that test accepts your code now. And numbers are mentioned only in description.

The kata was probably changed to add numbers in addition to alphabetic characters.

This is strange that this one is accepted cause it does not pass this example: "aA11" -> 2 # 'a' and '1'
It does not covers "numeric digits"
I think that the right RegEx is /([a-z,0-9])\1+/g