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.