This turns out to be because 10 is a composite number.
In fact, only 449 superabundant and highly composite numbers are the same.
Usually is given as a prime, but composite numbers work as well.
Twelve is also a highly composite number, the next one being 24.
It is particularly effective at splitting composite numbers with small factors.
The concept is somewhat analogous to that of highly composite numbers.
In contrast, the decision problem "is N a composite number?"
However, no finite set of bases is sufficient for all composite numbers.
Nine is a composite number, its proper divisors being 1 and 3.
One key is a large composite number, which the owner may distribute publicly.