[math-fun] Some Sum

What is the sum of the aliquot (proper) divisors of 3+i? a) The divisors are {1, 1+i, 1+2i, 3+i}. The sum of the first three numbers is 3+3i. b) Robert Spira (1961) defined a "complex sum of divisors" that is incorporated into Mathematica's DivisorSigma function: In[1]:= DivisorSigma[1,3+I] Out[1]= 2+6 I Of course that answer includes the divisor 3+i, so we subtract that from 2+6i to get -1+5i. c) Neither of the above. Spira's sum-of-divisors function is (I think) a product. So subtracting the 3+i after calculating the "sum" is a leap of faith.