19666589 has 2 divisors, whose sum is σ = 19666590. Its totient is φ = 19666588.

The previous prime is 19666571. The next prime is 19666607. The reversal of 19666589 is 98566691.

It is a balanced prime because it is at equal distance from previous prime (19666571) and next prime (19666607).

It can be written as a sum of positive squares in only one way, i.e., 18344089 + 1322500 = 4283^2 + 1150^2 .

It is an emirp because it is prime and its reverse (98566691) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19666589 - 2⁸ = 19666333 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19666289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9833294 + 9833295.

It is an arithmetic number, because the mean of its divisors is an integer number (9833295).

Almost surely, 2^19666589 is an apocalyptic number.

It is an amenable number.

19666589 is a deficient number, since it is larger than the sum of its proper divisors (1).

19666589 is an equidigital number, since it uses as much as digits as its factorization.

19666589 is an evil number, because the sum of its binary digits is even.

The product of its digits is 699840, while the sum is 50.

The square root of 19666589 is about 4434.7028085318. The cubic root of 19666589 is about 269.9249402694.

The spelling of 19666589 in words is "nineteen million, six hundred sixty-six thousand, five hundred eighty-nine".