1252099518401

This number is a prime.

                                                              125 2099518401

(4^4)^5 + (5^4)^4 is prime. Note that (4^4)^5 = 1099511627776, and after adding (5^4)^4 we obtain our prime number 1252099518401 which contains "09951" too! Note also that 9951 = 31*321 and 123*13 = 1599. [Kulsha]