Ah, sorry, my mistake. An 'Utterly Perfect' being would have to be 'all' but at the same time 'nothing', and everything 'in between', yet also not be. Essentially, to be 'utterly perfect', one would have to... Not be. It's something that contradicts itself because to exist it must not exist. Am I making sense?
Do note though, however, that this is 'utter perfection' rather than 'ordinary perfection' (and perfection is something people differ on the meaning of). Something 'ordinarily perfect' like a person who could live forever free of disease and pain, with no worries of death or sorrow, is something I consider possible. Of course, from then would the argument of 'is such an existence truly perfect' spring, but let's not go into that.
Omnipotence - at least the type the God of Christianity is seemingly represented as having (correct me if I'm wrong) - is something necessary for 'utter perfection' but is likewise also impossible, because of something so simple as... Well, doing anything, really. It cannot make it an object It cannot lift because It is omnipotent, but It cannot be omnipotent because It cannot make that object, the only remaining conclusion is that it was never such to begin with.
It's important to recognize that I am speaking in absolutes. Something with seemingly omnipotent power or 'the perfect being' from a human perspective could exist, but 'true' objective omnipotence, perfection, etc. are things that cannot possibly exist.