19723189 has 2 divisors, whose sum is σ = 19723190. Its totient is φ = 19723188.

The previous prime is 19723157. The next prime is 19723243. The reversal of 19723189 is 98132791.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18992164 + 731025 = 4358^2 + 855^2 .

It is an emirp because it is prime and its reverse (98132791) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19723189 - 2⁵ = 19723157 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19723129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9861594 + 9861595.

It is an arithmetic number, because the mean of its divisors is an integer number (9861595).

Almost surely, 2^19723189 is an apocalyptic number.

It is an amenable number.

19723189 is a deficient number, since it is larger than the sum of its proper divisors (1).

19723189 is an equidigital number, since it uses as much as digits as its factorization.

19723189 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27216, while the sum is 40.

The square root of 19723189 is about 4441.0797110613. The cubic root of 19723189 is about 270.1836382176.

The spelling of 19723189 in words is "nineteen million, seven hundred twenty-three thousand, one hundred eighty-nine".