22427...41183 (47-digits)

This number is a prime.

                         2242745 2848394140 2769470443 9799166361 1794141183

Smallest odd prime factor of (((((((((4^2-2)^2-2)^2-2)^2-2)^2-2)^2-2)^2-2)^2-2)^2-2)^2-2, a 586-digit Lucas-Lehmer number whose factorization will provide the first unknown term in OEIS A177892. [Mathar]