What will be the least number which when doubled will be exactly divisible by 12,18,21 and 30?

630 is the required answer
as the no.1260 is divisible individually by all 12,18,21 and 30 
we can remove this by just taking all necessary digits like 
2x2 from 12 
3x3 from 8
7 from 21 
and 5 from 30