Consider the numbers 51,87 and 115.

Now 51*87*115 = 510255 and [lcm(51-1 ,87-1, 115-1)= 122550

and 2^122550 = 104869 (mod510255)

Let D = gcd(104869 - 1,510255)

Is D divisible by 51, 87 or 115?

What can we conclude in terms of the primality of these three integers, if they don't divide D?