If the umber is of the form \prod_{n=1}^{k}p_n^{q_n} then the number of factors = \prod_{n=1}^{k}(q_n+1)
Because 5 is prime the number must be of the form p^4 where p is prime
We have the number of digits =2 and we should find p such that 9 \lt p^4 \lt 100
The only number that satsfies the condition is n = 2 and n is a prime and 2^4= 16
So 16 is the only 2 digit number having 5 factors
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