18686625776809 has 3 divisors (see below), whose sum is σ = 18686630099613. Its totient is φ = 18686621454006.

The previous prime is 18686625776747. The next prime is 18686625776821. The reversal of 18686625776809 is 90867752668681.

The square root of 18686625776809 is 4322803.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 18686625776809 - 2¹⁵ = 18686625744041 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18686625776849) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 2161402 + ... + 6484204.

It is an arithmetic number, because the mean of its divisors is an integer number (6228876699871).

Almost surely, 2^{18686625776809} is an apocalyptic number.

18686625776809 is the 4322803-rd square number.

18686625776809 is the 2161402-nd centered octagonal number.

It is an amenable number.

18686625776809 is a deficient number, since it is larger than the sum of its proper divisors (4322804).

18686625776809 is an frugal number, since it uses more digits than its factorization.

18686625776809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8645606 (or 4322803 counting only the distinct ones).

The product of its (nonzero) digits is 2926264320, while the sum is 79.

The spelling of 18686625776809 in words is "eighteen trillion, six hundred eighty-six billion, six hundred twenty-five million, seven hundred seventy-six thousand, eight hundred nine".