Please help me find this book title! I have been trying to recall what it is from almost thirty years, I read it as a teen. I think it was published in the 1980s.

The story takes place in a distant space faring future, where everyone is catalogued and designated by a galactic A.I. super-computer (space S.S.# of a sort). The galactic government is tyrannical, and a small time private detective is recruited to be the perfect weapon/spy to bring down the computer and government.

In this novel's universe, some people are born with mutations and abilities. The main character is a mutant who's power is that he can not be remembered for more than a day by anyone ever. Consequently, he is the perfect foil to this A.I. computer, as no one could ever remember him and to record his birth, thus is off the grid and he does not technically exist.

I recall that he also has either a mutation that has caused him to have one hand that is larger than the other or it's a transplanted hand from an African-American donor, but he is Caucasian (might not).