A litre is a unit of volume. You can observe this since the units are in terms of dm^3, or 1000 L = 1 m^3, exactly. However, your units are inverse volume. So more information is needed. For example, if your question is: "What volume is 141 kg of water", then we can answer the question.
1 kg of water is exactly 1 Liter. This was the original definition of the liter. So 141 kg or water is exactly 141 Liters of water.
If instead you are refering to a density, and you need to convert to kg / L, then remember that 1 m^3 = 1000 L. So substitute:
141 kg / m^3 = 141 kg / 1000 L = 0.141 kg / L
To find the ratio 141kg/m^3 in litres.
Numerator is in kilograms which is the mass unit. The denominator is in m^3 which is the volume unit. Therefore the ratio of mass per unit volume is the density.
But density is not measured in litres, as litre is equal to the of volume of 1000 cubic centimeter. However, if we want to express a the ratio of mass per litre of volume it is possible.
Therefore 141kg/m^3 = 141kg/ (1000litre), 1 m^3 = (100cm)^3 /1000 = 1000litre.
Therefore 141kg /m^3 = 141*1000 gram /(1000 litre) = 141gm/litre.
Threfore 141kg/m^3 and 141gram /litre are equivalent.