19989239 has 2 divisors, whose sum is σ = 19989240. Its totient is φ = 19989238.

The previous prime is 19989227. The next prime is 19989247. The reversal of 19989239 is 93298991.

It is a strong prime.

It is an emirp because it is prime and its reverse (93298991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19989239 - 2⁴ = 19989223 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19989209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9994619 + 9994620.

It is an arithmetic number, because the mean of its divisors is an integer number (9994620).

Almost surely, 2^19989239 is an apocalyptic number.

19989239 is a deficient number, since it is larger than the sum of its proper divisors (1).

19989239 is an equidigital number, since it uses as much as digits as its factorization.

19989239 is an evil number, because the sum of its binary digits is even.

The product of its digits is 314928, while the sum is 50.

The square root of 19989239 is about 4470.9326767465. The cubic root of 19989239 is about 271.3930698456.

The spelling of 19989239 in words is "nineteen million, nine hundred eighty-nine thousand, two hundred thirty-nine".