18685351687 has 4 divisors (see below), whose sum is σ = 18731948976. Its totient is φ = 18638754400.

The previous prime is 18685351679. The next prime is 18685351693. The reversal of 18685351687 is 78615358681.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78615358681 = 2459 ⋅31970459.

It is a cyclic number.

It is not a de Polignac number, because 18685351687 - 2³ = 18685351679 is a prime.

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18685351667) 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, 23298043 + ... + 23298844.

It is an arithmetic number, because the mean of its divisors is an integer number (4682987244).

Almost surely, 2^18685351687 is an apocalyptic number.

18685351687 is a deficient number, since it is larger than the sum of its proper divisors (46597289).

18685351687 is an equidigital number, since it uses as much as digits as its factorization.

18685351687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46597288.

The product of its digits is 9676800, while the sum is 58.

The spelling of 18685351687 in words is "eighteen billion, six hundred eighty-five million, three hundred fifty-one thousand, six hundred eighty-seven".