What is the time complexity factor?

Time complexity is measured relative to the size of the input, not its value. If your function takes a number, the size of its input is log of that number. Therefore, the time complexity of factorization is O(sqrt(2^n)) = O(2^(n/2)), it is exponential.
For More Information Please Refer:
https://stackoverflow.com/questions/33194931/when-can-an-algorithm-have-square-rootn-time-complexity
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