Yes, the system runs a special algorithm to verify that it is a valid number.

For each of the first 8 digits in the routing number, multiply it by the weight. Add the 8 results together, then substract the last digit of the sum from 10. The result should be equal to the 9th digit of the routing number. 

Example:                                                      

Routing number: 6  7  2  4  6  0  7  1  9                  

Last digit of 151 is 1, 10 - 1 = 9 which is the last digit of the routing number, so 672460719 is a good routing #.