18538840388 has 24 divisors (see below), whose sum is σ = 32911470144. Its totient is φ = 9135655200.

The previous prime is 18538840387. The next prime is 18538840393. The reversal of 18538840388 is 88304883581.

It is not an unprimeable number, because it can be changed into a prime (18538840387) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 936206 + ... + 955802.

It is an arithmetic number, because the mean of its divisors is an integer number (1371311256).

Almost surely, 2^18538840388 is an apocalyptic number.

It is an amenable number.

18538840388 is a deficient number, since it is larger than the sum of its proper divisors (14372629756).

18538840388 is a wasteful number, since it uses less digits than its factorization.

18538840388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23003 (or 23001 counting only the distinct ones).

The product of its (nonzero) digits is 5898240, while the sum is 56.

The spelling of 18538840388 in words is "eighteen billion, five hundred thirty-eight million, eight hundred forty thousand, three hundred eighty-eight".