any wierd calculator things?

i've noticed on a calsulator that can show 100 digits(in standard form that is) can only process a factorial equation up to the number 69....giving 1.7112 x10^98 while as 70 is precieved as math error.... given that 69! is only 1.7112 i then tried 69.1... math error 69.000001... eath error and so one. i wonder y calculators cant go above 69 when its not its 100 digit limit

The ! operator can only be applied to natural numbers. For real numbers you can use the gamma function but I doubt any standard calculators implement that directly. And 70! just causes overflow.

As for when the overflow occurs:
(%i1) find_root(gamma(x+1)=10^100,x,69,70);
(%o1) 69.95757445735353