Additional Factorial Set

There is only one Additional Factorial Set, which is 6.

The factors of 6 are 1, 2, 3, and 6.

If you add all factors except the last (which is the same as the resulting factored answer), you receive the same answer (6).

1+2+3 = 6;
2 + 3 = 5; 5 + 1 = 6;

So far, 6 is the only number that is able to do this.