1666911 has 4 divisors (see below), whose sum is σ = 2222552. Its totient is φ = 1111272.

The previous prime is 1666909. The next prime is 1666913. The reversal of 1666911 is 1196661.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1196661 = 3 ⋅398887.

It is an interprime number because it is at equal distance from previous prime (1666909) and next prime (1666913).

It is not a de Polignac number, because 1666911 - 2¹ = 1666909 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666913) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 277816 + ... + 277821.

It is an arithmetic number, because the mean of its divisors is an integer number (555638).

2^1666911 is an apocalyptic number.

1666911 is a deficient number, since it is larger than the sum of its proper divisors (555641).

1666911 is an equidigital number, since it uses as much as digits as its factorization.

1666911 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 555640.

The product of its digits is 1944, while the sum is 30.

The square root of 1666911 is about 1291.0890751610. The cubic root of 1666911 is about 118.5689036506.

The spelling of 1666911 in words is "one million, six hundred sixty-six thousand, nine hundred eleven".