C Assignment Help

I'm in college and I have to do an assignment on Abundant Numbers (Programmed in C).

Assignment Details are pretty straight forward. Ask for a number determine if it is abundant.
-Use "boolean" function to test a number for abundance.
-use a function to control output and another for input.
-An Abundant Number is a positive integer whose integer factors less than itself sum to a value greater than it.

This is the Code I have so far:

Code:

---

#include <stdio.h>

#include <math.h>



int Input(int N)

{

        printf("Enter the Nth Abundant Number you wish to see: ");

        scanf("%d", &N);

        return(N);

}



int Calc(int N)

{

        int Sum, I, I2;

 

        Sum = 0;

        I2 = sqrt(N);



        for (I = 1; I >= I2; I++)

                if ((N % I) = 0) Sum += I + (N / I);



        return(Sum);

}



int Check(int N, int Sum, int Abundancy)

{

        if (Sum > N)

                Abundancy = 1;

        else

                Abundancy = 0;



        return(Abundancy);

}



int Output(int Number, int Abundancy)

{

        if (Abundancy == 1)

                printf("%d %s", Number, "is Abundant");

        else

                printf("%d %s", Number, "is not Abundant");

}



int main()

{

        /* Variables */

        int N, Sum;

        int Abundancy;

       

        /* Start Loop */

        while (N != 0)

        {

                /* Input */

                N = Input(N);

                for(int I = N; I = (N - 10)or I <= 0; I--)

                {

                        /* Calculate */

                        Sum = Calc(N);               



                        /* Determine Abundancy */

                        Abundancy = Check(N, Sum, Abundancy);               

               

                        /* Output */

                        Output(N, Abundancy);

                }

        }       

}

---

Could someone help me figure out why it declares everything as not an abundant number?
my test is 12. 1 + 2 + 3+ 4+ 6 = 16, 16 > 12, so it is abundant.

>> for (I = 1; I >= I2; I++)
Why use I as variable name?! Review the loop condition.