Formula Used as a Serial Number

Hello,

I'm looking for some assistance with a formula. I'm using the formula below, as a serial number, for part of a barcode. It's worked fine for the past year, but now the requirements have changed. The complete barcode scans with 22 characters and now needs to be shortened to 20. The first part of the barcode can't be altered. So that leaves the serial number which consists of 9 digits. The number 8 is static and can be removed, but I'm still left with a total of 21. I've been unable to find a solution and would appreciate the assistance.

"8"&(totext(datadate,"MMdd")+totext(datatime,"mmss"))