18908688321 has 6 divisors (see below), whose sum is σ = 27312549810. Its totient is φ = 12605792208.

The previous prime is 18908688287. The next prime is 18908688341. The reversal of 18908688321 is 12388680981.

It can be written as a sum of positive squares in only one way, i.e., 15509215296 + 3399473025 = 124536^2 + 58305^2 .

It is not a de Polignac number, because 18908688321 - 2⁷ = 18908688193 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18908688341) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1050482676 + ... + 1050482693.

It is an arithmetic number, because the mean of its divisors is an integer number (4552091635).

Almost surely, 2^18908688321 is an apocalyptic number.

It is an amenable number.

18908688321 is a deficient number, since it is larger than the sum of its proper divisors (8403861489).

18908688321 is a wasteful number, since it uses less digits than its factorization.

18908688321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2100965375 (or 2100965372 counting only the distinct ones).

The product of its (nonzero) digits is 1327104, while the sum is 54.

The spelling of 18908688321 in words is "eighteen billion, nine hundred eight million, six hundred eighty-eight thousand, three hundred twenty-one".