Very subjective, I would say a humble person would not say that he is smart, there is much more to that. Theorists say that intelligence covers many aspects, like logic, interpersonal, linguistics, like which category. Not just mathematicians. Some go with IQ scores, some say it is the ability to 'go with the flow' with your surroundings... (socially? well in that case I am not intelligent!) Some will say you're a genius if you find a cure for cancer. For me, it is such a general term, for example, I wouldn't say " I am smart in science" I would say "I scored X% better than all people who took that exam"

Don't classify yourself, human beings are always learning