the smallest possible number which is divisible by 3 and 5 or 7 represented by 2 digits either 0 or 1 then the maximum number of digits required to represented it is
The smallest such number is 3*5*7 = 105
Since 64 <= 105 < 128
or
2^6 <= 105 < 2^7
That will require 7 digits: 1101001