If you write your operator as a free function, rather than a class member, you can specify both operands.
Complex operator/ (int lhs, Complex rhs);
Complex operator/ (Complex lhs, int rhs);
You might have to make them a friend function, if you need to access private members.
(I'll leave it to you to decide whether you need int, or float, or whatever at the front.)
EDIT: A bit fuller example might be:
Complex operator/ (int lhs, Complex rhs) {
Complex answer;
double mag = rhs.real*rhs.real+rhs.imag*rhs.imag;
answer.real = lhs*rhs.real/mag;
answer.imag = -lhs*rhs.imag/mag;
return answer;
}
and then a bit later:
f = 6/f;
(again I'm assuming public member variables for ease of use).