Iron contains 8.5 x 1028 atoms/m3 at saturation the alignment of the electrons spin magnetic moments in

Question:

Iron contains 8.5 x 1028 atoms/m3 at saturation the alignment of the electrons’ spin magnetic moments in iron can contribute 1.5 T to the total magnetic flux density B. If the spin magnetic moment of a single electron is 9.27 x 10-24 (A.m2), how many electrons per atom contribute to the saturated field?