Verified by LLR, this PRP is B9(0^45019)E5 when written in base 21, and (assuming its primality) is the 13381st "base 21 minimal prime" as described on http://primes.utm.edu/glossary/xpage/MinimalPrime.html if we only count the primes > base and ruled out the primes <= base, in base 21 there are 12 unsolved families when searched to length 50000, see https://github.com/xayahrainie4793/minimal-elements-of-the-prime-numbers for more information.

To be completed...