The product of all the prime numbers less than 20 is closet to which of the folowing powers of 10?
10^9
10^8
10^7
10^6
10^5
[spoiler]10^7[/spoiler]
10^9
10^8
10^7
10^6
10^5
[spoiler]10^7[/spoiler]
Is the answer 10^6?
I just ran it through my head roughly...we can see that 2*3*5*7 = 210.
All the prime numbers after that will add a 0 to the end of the 210 because each is greater than 10, but less than 20. So, we have 11, 13, 17, 19...we add 4 zeros which gives us 2100000. That would be closest to 10^6 I believe.
I know there are others here much better at this than I, so I hope someone will correct me if I'm wrong.
