18889919 has 2 divisors, whose sum is σ = 18889920. Its totient is φ = 18889918.

The previous prime is 18889909. The next prime is 18889921. The reversal of 18889919 is 91998881.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18889919 - 2²⁴ = 2112703 is a prime.

It is a super-2 number, since 2×18889919² = 713658079653122, which contains 22 as substring.

Together with 18889921, 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 (18889909) 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, 9444959 + 9444960.

It is an arithmetic number, because the mean of its divisors is an integer number (9444960).

Almost surely, 2^18889919 is an apocalyptic number.

18889919 is a deficient number, since it is larger than the sum of its proper divisors (1).

18889919 is an equidigital number, since it uses as much as digits as its factorization.

18889919 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 373248, while the sum is 53.

The square root of 18889919 is about 4346.2534440596. The cubic root of 18889919 is about 266.3238325220.

The spelling of 18889919 in words is "eighteen million, eight hundred eighty-nine thousand, nine hundred nineteen".