Is "am I not" the question tag in the sentence "I am an interesting person"?
Yes.
Indeed, 'aren't I?' is far more common in all but fairly formal writing and very formal speech in BrE.
and indeed "'n'I?". 'Am I not?' is often used to sound extremely formal: 'I am right - am I not? - in supposing that you made no attempt to ...'.
b
I believe "Am I not?" is colloquial in North East England, but I could be wrong![]()