Found with PFGW Version 3.7.5

1887^6860-6860^1887 is 2-PRP! (17.7146s+0.0100s)
1887^6860-6860^1887 is 3-PRP! (18.2447s+0.0009s)
1887^6860-6860^1887 is 5-PRP! (17.9106s+0.0014s)
1887^6860-6860^1887 is 7-PRP! (17.1022s+0.0008s)
1887^6860-6860^1887 is 11-PRP! (19.4673s+0.0015s)

Primality testing 1887^6860-6860^1887 [N-1/N+1, Brillhart-Lehmer-Selfridge]
Running N-1 test using base 11
Running N-1 test using base 13
Running N+1 test using discriminant 31, base 3+sqrt(31)
Calling N-1 BLS with factored part 0.06% and helper 0.02% (0.20% proof)
1887^6860-6860^1887 is Fermat and Lucas PRP! (105.3776s+0.0021s)

To be completed...