2.1 liters is the same as: -cm3 and - ml

To convert liters to mL, all you need to do is move the decimal three times to the right or multiply by 1000.

2.1 Liter = 2100 mL

then, to change to cm-3 is really easy because 1 ml is same as 1 cm-3

so, 2100 mL= 2100 cm-3