It really depends on how you performed your computations. Let's take a somewhat large number, 3^40.
xDouble = 3^40;
xUint64 = uint64(3)^40;
areTheseTheSame = [uint64(xDouble); xUint64]
The answer to the implied question is no. The reason the two elements of areTheseTheSame are not the same is that 3^40 is greater than flintmax.
isGreaterThanFlintmax = xDouble > flintmax
The key statement in the flintmax documentation is "Above this value, double-precision format does not have integer precision, and not all integers can be represented exactly." The next largest representable number above flintmax is not flintmax+1 but flintmax+2.
>> F1 = flintmax;
>> F2 = flintmax + 1;
>> F1 == F2
>> F3 = flintmax + 2;
>> F1 == F3
However, 3^40 is less than the maximum value that you can store in a uint64 so it can be exactly represented in uint64.
isLessThanMaximumUint64 = xUint64 < intmax('uint64')
If your computations are likely to result in large (greater than flintmax) integer values, you should probably operate on values stored in an integer data type as much as you can, like I did when I computed xUint64 by computing mpower (the ^ operator) on a uint64 value.