It\'s quite easy to see that n! grows slower than almost anything to the N power (say, 100^N) and so, if a problems is considered NP complete and one happened upon a n! algorith
It's quite easy to see that the factorial is (approximately) exponential in behaviour.
It can be (very crudely) approximated as nn (more specifically, sqrt(2πn)(n/e)n).
So if you have found any specific M where you think Mn is a good approximation, you're (probably) wrong. 269! is larger than 100n and as n! will be multiplied by numbers larger than 100, it will continue to grow faster.