Is the answer to be 14 microlitre if the MW is 8905.
No, can't be MW 8905 is in Da you need g/ml.
If the primer sheet or label doesn't have it, it might have the amount of oligo
ex. amount of oligo =12.1OD260 =60.40nMoles =0.38mg
From that you could get grams/mol if you wanted (mg/nMoles convert to g/mol), but you can go straight to 0.38mg divided by volume to make stock solution, say 604ul (100uM stock in example).
You would have 380ug/604ul = 0.63ug/ul ---conversions--->
0.63ug/ul * 1000ul/ml * 1g/1000000ug = 0.000630g/ml