Sieved with NewPGen, found to be a 3-PRP with PFGW, and confirmed with LLR.
2^274464-238319 is 3-PRP! (39.2898s+0.0002s)
2^274464-238319 is Fermat, Lucas and Frobenius PRP! (P = 5, Q = 3, D = 13) Time : 153.623 sec.

To be completed...