Filzian number

A Filzian number is a positive integer that is equal to sum
of its digits times the product of its digits.


For example,

(1 + 3 + 5) * 1 * 3 * 5 = 135

(1 + 4 + 4) * 1 * 4 * 4 = 144


(a) Find another one
(b) Find a general solution