What is the smallest number with 16 factors?

Well, isn't that a happy little question! The smallest number with 16 factors is 60. You see, when you break down 60 into its prime factors (2, 2, 3, 5), you can use the formula (a+1)(b+1)(c+1)... where a, b, c are the exponents of the prime factors to find the total number of factors.