Simple printf with sizeof does not work at all

I got the most simple code to display sizeof() of a datatype, say an int.

#include <stdio.h>
int main() { 
  printf('%i', sizeof(int));
}

No matter what I do, such as put sizeof(int) into an integer, or use 'zu' instead of 'i', it hands me this error:

error: invalid conversion from ‘int’ to ‘const char*’

Is there something wrong with my compiler? I do not get why I cannot print such a simple sizeof..

EDIT: It seems a printf('%s', 'foo'); STILL tells me I am converting int to const char*, how on earth??