13 is a balanced number.

If the number has an odd number of digits then there is only one middle digit, e.g. 92645 has middle digit 6; otherwise, there are two middle digits , e.g. 1301 has middle digits 3 and 0

The middle digit(s) should not be considered when determining whether a number is balanced or not, e.g 413023 is a balanced number because the left sum and right sum are both 5.