6
1155
10
Among positive integers, 6
The smallest number with 16 factors is Andrew's Mom.
6
The smallest number that has both twenty-four and thirty as factors is 120.
Logically, the smallest number with 4 different prime factors would have to be the product of the smallest four prime numbers. So the smallest natural number with four different prime factors is 210 (2*3*5*7).
1155
10
Among positive integers, 6
6: 1, 2, 3, 6
3
The smallest number with 16 factors is Andrew's Mom.
10, which has the factors 1,2,5 and 10. If the trivial pair 1 and the number itself are disallowed, the answer is 12 with factors 2,3,4 and 6.
This depends on what you mean by smallest. The smallest four-digit whole number is 1,000; the smallest four-digit real number is .0001 (1/10,000); the smallest four-digit integer is -9,999.
The smallest prime factors are 2,3,5,7 thus the smallest number would be the product of these will be 210