The coordination number of an atom in a body-centered cubic structure is _______.
[Assume that the lattice is made up of atoms.]

An element with molar mass 2.7 $$ \times $$ 10^-2 kg mol^-1 forms a cubic unit cell with edge length 405 pm. If its density is 2.7 $$ \times $$ 10³ kg m^-3, the radius of the element is approximately ______ $$ \times $$ 10^-12 m (to the nearest integer).