What is the divisibility rule of 11
add up the odd-numbered positions of digits,
then add up the even-numbered positions of digits.
e.g. 3365208
add the 1st, the 3rd, the 5th and the 7th = 19
add the 2nd, the 4th, and the 6th = 8
If these two sums are the same, or their difference is a multiple of 11, then the big number is divisible by 11
that is, 19-8 = 11, so we are good
another example:
4562147
4+6+1+7 = 18
5+2+4 = 11
18-11 = 7 Not a multiple of 11, so
456147 is not divisible by 11