# Numbers that are the sum of the squares of their prime factors?

A number which is equal to the sum of the squares of its prime factors with multiplicity: - $16=2^2+2^2+2^2+2^2$ - $27=3^2+3^2+3^2$ Are these the only two such numbers to exist? There has to be an easy proof for this, but it seems to elude me. Thanks