18678328321 has 4 divisors (see below), whose sum is σ = 18686175444. Its totient is φ = 18670481200.

The previous prime is 18678328307. The next prime is 18678328343. The reversal of 18678328321 is 12382387681.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3901251600 + 14777076721 = 62460^2 + 121561^2 .

It is a cyclic number.

It is not a de Polignac number, because 18678328321 - 2¹⁷ = 18678197249 is a prime.

It is a Smith number, since the sum of its digits (49) 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 not an unprimeable number, because it can be changed into a prime (18678328301) 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, 3919990 + ... + 3924751.

It is an arithmetic number, because the mean of its divisors is an integer number (4671543861).

Almost surely, 2^18678328321 is an apocalyptic number.

It is an amenable number.

18678328321 is a deficient number, since it is larger than the sum of its proper divisors (7847123).

18678328321 is an equidigital number, since it uses as much as digits as its factorization.

18678328321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7847122.

The product of its digits is 774144, while the sum is 49.

The spelling of 18678328321 in words is "eighteen billion, six hundred seventy-eight million, three hundred twenty-eight thousand, three hundred twenty-one".