The definition of density is the mass per volume of the substance. This is an intrinsic property therefore the size (or any external feature) does not change this property.
For aluminum, it is given that it has a density of 2.70 x 10^3 kg/m^3.
The problem states that there is an aluminum substance having a volume of 1.50 m^3
Mass of aluminum = (1.50 m^3)( 2.70 x 10^3 kg/m^3) = 4050 kg