想写一个找出大于N的最小素数的函数，但是自己的代码上传是错的，请问出错在哪

#include<stdio.h>
int Prime_number ( int N );
int main()
{ 
    int num;
     scanf("%d",&num);
     printf("%d\n",Prime_number(num));
     return 0;
}
int Prime_number ( int N )
{
    int num=N+1,j;
        for(j=2;j<10;j++)
        {
            if(num%j!=0)
                break;
                else
                num++;
        } 
    return num;
}

#include<stdio.h>
#include<math.h>
int Prime_number ( int N );
int main()
{ 
     int num;
     scanf("%d",&num);
     printf("%d\n",Prime_number(num));
     return 0;
}
int Prime_number ( int N )
{
    int num=N+1,j;
    while(1)
    {
        for(j=2;j<=sqrt(num);j++)
        {
            if(num%j==0)
            {
                break;
            }
        } 
        if(j>sqrt(num))
           break;
        num++;
    }
    return num;
}

 
#include<stdio.h>
int Prime_number ( int N );
int main()
{ 
    int num;
     scanf("%d",&num);
     printf("%d\n",Prime_number(num));
     return 0;
}
int Prime_number ( int N )
{
    while(1)
    {
        for(j=2;j<N;j++)
        {
            if(N%j==0)
                break;
        } 
        if(j==N)
            break;
        N++;
     }
     return N;
}