#include <bits/stdc++.h>
using namespace std;
long long demuoc (long long n)
{
    long long d = 0;
    for (long long i = 1; i <= sqrt(n); ++i)
    {
        if (n % i == 0)
        {
            d += 2;
        }
    }
    long long k = sqrt(n);
    if (k * k == n) d -= 1;
    return d;
}
bool check (long long x)
{
    for (long long i = 2; i <= sqrt(x); ++i)
    if (x % i == 0) return false;
    return x > 1;
}
long long d = 0, n;
int main()
{
    cin >> n;
    for (long long i = 1; i <= sqrt(n); ++i)
    {
        if (n % i == 0)
        {
            if (i == n / i)
            {
                if (check(i)) d++;
            }
            else 
            {
                if (check(i)) d++;
                if (check(n / i)) d++;
            }
        }
    }
    cout << demuoc(n) - d;
}

Đây nha

#include<bits/stdc++.h>
using namespace std;
#define ll long long
ll a[10000007];
int main()
{
  ll n;
  cin>>n;
  ll k=2;
  ll dem=0;
  ll ans=1;
  while(n>0&&k*k<=n)
  {
    while(n%k==0)
    {
      a[k]++;
      n/=k;
    }
    k++;
  }
  if(n>1)
  {
      dem++;
      ans=2;
  }
  for(ll i=2;i<=k;i++)
  {
    if(a[i]!=0)
    {
      dem++;
      ans=ans*(a[i]+1);
    }
  }
  cout<<ans-dem;
}