18989879 has 2 divisors, whose sum is σ = 18989880. Its totient is φ = 18989878.

The previous prime is 18989863. The next prime is 18989897. The reversal of 18989879 is 97898981.

Together with next prime (18989897) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is an emirp because it is prime and its reverse (97898981) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18989879 - 2⁴ = 18989863 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18989899) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9494939 + 9494940.

It is an arithmetic number, because the mean of its divisors is an integer number (9494940).

Almost surely, 2^18989879 is an apocalyptic number.

18989879 is a deficient number, since it is larger than the sum of its proper divisors (1).

18989879 is an equidigital number, since it uses as much as digits as its factorization.

18989879 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2612736, while the sum is 59.

The square root of 18989879 is about 4357.7378305722. The cubic root of 18989879 is about 266.7927759426.

The spelling of 18989879 in words is "eighteen million, nine hundred eighty-nine thousand, eight hundred seventy-nine".