SmarterTrack's ticket numbers are randomly generated. There is not a way to modify the ticket number to get a sequential order instead. This is, in part, to prevent users from guessing the next ticket number in the rotation and submitting a ticket they they may not be authorized to submit, such an unpaid support ticket.
This feature request has been discussed in the past. Because SmarterTrack's ticketing system heavily relies on the ticket number as it is generated now, this is not a feature that will be changed in the near future. However, we have considered other changes to make the ticket number more user friendly, such as changing where the ticket number is displayed - removing it from the subject line, adding it as a Custom Field, etc.