18986839 has 2 divisors, whose sum is σ = 18986840. Its totient is φ = 18986838.

The previous prime is 18986837. The next prime is 18986857. The reversal of 18986839 is 93868981.

It is a weak prime.

It is an emirp because it is prime and its reverse (93868981) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18986839 - 2¹ = 18986837 is a prime.

Together with 18986837, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18986837) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9493419 + 9493420.

It is an arithmetic number, because the mean of its divisors is an integer number (9493420).

Almost surely, 2^18986839 is an apocalyptic number.

18986839 is a deficient number, since it is larger than the sum of its proper divisors (1).

18986839 is an equidigital number, since it uses as much as digits as its factorization.

18986839 is an evil number, because the sum of its binary digits is even.

The product of its digits is 746496, while the sum is 52.

The square root of 18986839 is about 4357.3890117822. The cubic root of 18986839 is about 266.7785386512.

The spelling of 18986839 in words is "eighteen million, nine hundred eighty-six thousand, eight hundred thirty-nine".