1666339 has 2 divisors, whose sum is σ = 1666340. Its totient is φ = 1666338.

The previous prime is 1666321. The next prime is 1666351. The reversal of 1666339 is 9336661.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (9336661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1666339 - 2⁵ = 1666307 is a prime.

It is not a weakly prime, because it can be changed into another prime (1666309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833169 + 833170.

It is an arithmetic number, because the mean of its divisors is an integer number (833170).

2^1666339 is an apocalyptic number.

1666339 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666339 is an equidigital number, since it uses as much as digits as its factorization.

1666339 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17496, while the sum is 34.

The square root of 1666339 is about 1290.8675377435. The cubic root of 1666339 is about 118.5553398046. Note that the first 3 decimals are identical.

The spelling of 1666339 in words is "one million, six hundred sixty-six thousand, three hundred thirty-nine".