18516668687 has 4 divisors (see below), whose sum is σ = 20200002216. Its totient is φ = 16833335160.

The previous prime is 18516668659. The next prime is 18516668699. The reversal of 18516668687 is 78686661581.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78686661581 = 11 ⋅7153332871.

It is a cyclic number.

It is not a de Polignac number, because 18516668687 - 2⁶ = 18516668623 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18516668647) 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, 841666748 + ... + 841666769.

It is an arithmetic number, because the mean of its divisors is an integer number (5050000554).

Almost surely, 2^18516668687 is an apocalyptic number.

18516668687 is a deficient number, since it is larger than the sum of its proper divisors (1683333529).

18516668687 is a wasteful number, since it uses less digits than its factorization.

18516668687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1683333528.

The product of its digits is 23224320, while the sum is 62.

The spelling of 18516668687 in words is "eighteen billion, five hundred sixteen million, six hundred sixty-eight thousand, six hundred eighty-seven".