Found with PFGW Version 3.6.0

90^21819-89 is 2-PRP! (35.3418s+0.0024s)
90^21819-89 is 3-PRP! (31.6308s+0.0024s)
90^21819-89 is 5-PRP! (31.1143s+0.0029s)
90^21819-89 is 7-PRP! (31.5853s+0.0026s)
90^21819-89 is 11-PRP! (31.9982s+0.0024s)

Primality testing 90^21819-89 [N-1/N+1, Brillhart-Lehmer-Selfridge]
Running N-1 test using base 3
Running N+1 test using discriminant 7, base 6+sqrt(7)
Calling N-1 BLS with factored part 0.01% and helper 0.01% (0.05% proof)
90^21819-89 is Fermat and Lucas PRP! (196.4532s+0.0038s)

To be completed...