1666589 has 2 divisors, whose sum is σ = 1666590. Its totient is φ = 1666588.

The previous prime is 1666559. The next prime is 1666597. The reversal of 1666589 is 9856661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1092025 + 574564 = 1045^2 + 758^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1666589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1666519) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833294 + 833295.

It is an arithmetic number, because the mean of its divisors is an integer number (833295).

2^1666589 is an apocalyptic number.

It is an amenable number.

1666589 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666589 is an equidigital number, since it uses as much as digits as its factorization.

1666589 is an evil number, because the sum of its binary digits is even.

The product of its digits is 77760, while the sum is 41.

The square root of 1666589 is about 1290.9643682147. The cubic root of 1666589 is about 118.5612684407.

The spelling of 1666589 in words is "one million, six hundred sixty-six thousand, five hundred eighty-nine".