what is the smallest number divisible by 15,20,24,32,36

The smallest number divisible by 15,20,24,32,36 can be find out by taking their LCM as:

So, LCM of  15,20,24,32,36 = 2 × 2 × 2 × 2 × 2 × 3 × 3 × 5 = 1440.

Hence, 1440 is the smallest number which is divisible by each of 15,20,24,32 and 36.