45644domain: NAppears in sequencesNon-palindromic numbers such that the two largest proper divisors are palindromes having at least two digits and no other divisor is a palindrome with at least two digits.at n=27A074889k such that 2kp+1 is the first factor of a nonprime Mersenne number M(p) = 2^p - 1.at n=40A079324