Product of Primes

Given two numbers L and R (inclusive) find the product of primes within this range. Print the product modulo 109+7. If there are no primes in that range you must print 1.

• Time : O((r-l)sqrt(r))
• Space : O(1)

class Solution{
    long long mod = 1e9 + 7;
    bool isPrime(long long n) {
        for(long long i = 2; i * i <= n; i++)
            if(n % i == 0) return false;
        return true;
    }
public:
    long long primeProduct(long long L, long long R){
        long long res = 1;
        for(long long i = L; i <= R; i++) {
            if(!(i & 1)) continue;
            if(isPrime(i)) res = (res * i) % mod;
        }
        if(L <= 2 and 2 <= R) res *= 2;
        return res % mod;
    }
};