Hello,
606 is divisble by 2 since 6 is divisible by 2 (last digit).
606 is divisible by 3 since 6+0+6=12 which is divisible by 3
606 is not divisible by 4 since 04 is not divisible by 4 (last 2 digits)
606 is divisible by 6 since 606 is divisible by 2 and by 3 thus by 6.