18997439 has 2 divisors, whose sum is σ = 18997440. Its totient is φ = 18997438.

The previous prime is 18997427. The next prime is 18997441. The reversal of 18997439 is 93479981.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18997439 - 2¹² = 18993343 is a prime.

Together with 18997441, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18997409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9498719 + 9498720.

It is an arithmetic number, because the mean of its divisors is an integer number (9498720).

Almost surely, 2^18997439 is an apocalyptic number.

18997439 is a deficient number, since it is larger than the sum of its proper divisors (1).

18997439 is an equidigital number, since it uses as much as digits as its factorization.

18997439 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 489888, while the sum is 50.

The square root of 18997439 is about 4358.6051667936. The cubic root of 18997439 is about 266.8281752517.

The spelling of 18997439 in words is "eighteen million, nine hundred ninety-seven thousand, four hundred thirty-nine".