18986635209 has 4 divisors (see below), whose sum is σ = 25315513616. Its totient is φ = 12657756804.

The previous prime is 18986635177. The next prime is 18986635271. The reversal of 18986635209 is 90253668981.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 18986635209 - 2⁵ = 18986635177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18986635909) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3164439199 + ... + 3164439204.

It is an arithmetic number, because the mean of its divisors is an integer number (6328878404).

Almost surely, 2^18986635209 is an apocalyptic number.

It is an amenable number.

18986635209 is a deficient number, since it is larger than the sum of its proper divisors (6328878407).

18986635209 is an equidigital number, since it uses as much as digits as its factorization.

18986635209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6328878406.

The product of its (nonzero) digits is 5598720, while the sum is 57.

The spelling of 18986635209 in words is "eighteen billion, nine hundred eighty-six million, six hundred thirty-five thousand, two hundred nine".