what is the common denominator of the numbers "13, 16, 17"?

It's 1, since 13 and 17 are prime.

Since 2 of the 3 numbers are prime, there are no common factors other than 1. So your LCD is the product of the three numbers.

13 * 16 * 17 = 3536

13 = 13
16 = 2 x 2 x 2 x 2
17 = 17
--------------------------
2 x 2 x 2 x 2 x 13 x 17
= 3536

The common denominators are:
3536 x 1 = 3536
3536 x 2 = 7072
3536 x 3 = 10608
3536 x 4 = 14144
... ...

Only 1.

And if you multiply them it's an LCM (Lowest Common Multiple)

these numbers do not have a common denominator

what the other guys said is right , two of the #s are prime so its 1

there is no common factors for these three numbers, so the GCD = ( 13 ) ( 16 ) ( 17 )
GCD = 3536.

With common factors you don't just multiply the numbers together.