Normal sudoku rules apply. Orthogonally adjacent cells do not contain consecutive digits. Digits in a cage do not repeat and sum to a perfect number. A perfect number is a number that equals the sum of its proper divisors (i.e. each divisor excluding the number itself). For example, 20 is not a perfect number since the sum of the proper divisors is 1+2+4+5+10=22, which is not 20. [Hint: There are only two perfect numbers that are less than 45]