18985887817 has 8 divisors (see below), whose sum is σ = 20568776256. Its totient is φ = 17420490192.

The previous prime is 18985887799. The next prime is 18985887829. The reversal of 18985887817 is 71878858981.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18985887817 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18985887857) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4370443 + ... + 4374784.

It is an arithmetic number, because the mean of its divisors is an integer number (2571097032).

Almost surely, 2^18985887817 is an apocalyptic number.

It is an amenable number.

18985887817 is a deficient number, since it is larger than the sum of its proper divisors (1582888439).

18985887817 is a wasteful number, since it uses less digits than its factorization.

18985887817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8745407.

The product of its digits is 72253440, while the sum is 70.

The spelling of 18985887817 in words is "eighteen billion, nine hundred eighty-five million, eight hundred eighty-seven thousand, eight hundred seventeen".