On the W-2, Box 12 Code D is for Elective Deferrals to a 401(k) plan. Is it possible you contributed $19,805.66 to your retirement plan? It could be that the comma printed out very lightly or not at all..
You can subtract the amount in Box 1 from the amount in Box 3. It should give you the amount in Box 12, Code D (or close to it).
To be sure, contact your payroll office.
