1666943 has 2 divisors, whose sum is σ = 1666944. Its totient is φ = 1666942.

The previous prime is 1666939. The next prime is 1666991. The reversal of 1666943 is 3496661.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1666943 - 2² = 1666939 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1666913) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833471 + 833472.

It is an arithmetic number, because the mean of its divisors is an integer number (833472).

2^1666943 is an apocalyptic number.

1666943 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666943 is an equidigital number, since it uses as much as digits as its factorization.

1666943 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23328, while the sum is 35.

The square root of 1666943 is about 1291.1014677399. The cubic root of 1666943 is about 118.5696623755.

The spelling of 1666943 in words is "one million, six hundred sixty-six thousand, nine hundred forty-three".