Existence of Integers with Multiplicative Persistence Greater than 11

Theorem

It is not known whether there exists a number $n$ such that:

$P \left({n}\right) = 12$

where $P \left({n}\right)$ denotes the multiplicative persistence of $n$.

Progress

If there is such a number $n$, it is greater than $10^{200}$.

Sources

• 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $277,777,788,888,899$