求整除度的有效方法

Professor says this isn't a efficient algorithm to check whether the number is divisible by a number from 100,000-150,000. I'm having trouble finding a better way. Any help would be appreciated.

unsigned short divisibility_check(unsigned long n){
    unsigned long i;
    for(i=100000; i<=150000;i++){
        if(n%i == 0){
            return 0;
        }
    }
    return 1;
}