Can not vs. Cannot vs. Can't

The Difference Between Can not and Cannot

Cannot/can't means "be not able to". Cannot and can't are not the same as 'Can not'. You may see or use 'can not' only when 'not' is a part of another phrase like " .....not only .... but also.....".
Correct: I cannot sing
NOT: I can not sing
Correct: I can not only sing but also dance
NOT: I cannot only sing but also dance

The Difference Between Cannot and Can't

Can't is the contraction of Cannot.
Cannot is used in formal writing and formal speech
Can't is used in informal writing and informal speech