18973439 has 2 divisors, whose sum is σ = 18973440. Its totient is φ = 18973438.

The previous prime is 18973433. The next prime is 18973441. The reversal of 18973439 is 93437981.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18973439 is a prime.

Together with 18973441, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18973439.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18973433) 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, 9486719 + 9486720.

It is an arithmetic number, because the mean of its divisors is an integer number (9486720).

Almost surely, 2^18973439 is an apocalyptic number.

18973439 is a deficient number, since it is larger than the sum of its proper divisors (1).

18973439 is an equidigital number, since it uses as much as digits as its factorization.

18973439 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 163296, while the sum is 44.

The square root of 18973439 is about 4355.8511223411. The cubic root of 18973439 is about 266.7157640501.

The spelling of 18973439 in words is "eighteen million, nine hundred seventy-three thousand, four hundred thirty-nine".