Two first thoughts, not necessarily useful or correct. Isn't that bound essentially just $n$? I think you have to factor $n$ first. Then: why do you need to know? How large will $n$ be in practice (if it's a practical matter)>
– Ethan BolkerMay 06 '18 at 18:02
We can assume that the factors is available from outside (eg from a quantum computer - Shor algorithm).
– AurelioMay 06 '18 at 18:09
If $n$ is $k$-th primorial then just the number of multiplicative partitions of $n$ is $k$-th Bell number. The $k\to\infty$ asymptotics of logarithms of these coinside, right? (It is towards the negative answer.)
– metamorphyMay 06 '18 at 18:16