18131239388 has 24 divisors (see below), whose sum is σ = 33132661632. Its totient is φ = 8665322864.

The previous prime is 18131239387. The next prime is 18131239393. The reversal of 18131239388 is 88393213181.

It is a super-2 number, since 2×18131239388² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18131239387) 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, 62231 + ... + 200337.

It is an arithmetic number, because the mean of its divisors is an integer number (1380527568).

Almost surely, 2^18131239388 is an apocalyptic number.

It is an amenable number.

18131239388 is a deficient number, since it is larger than the sum of its proper divisors (15001422244).

18131239388 is a wasteful number, since it uses less digits than its factorization.

18131239388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139561 (or 139559 counting only the distinct ones).

The product of its digits is 248832, while the sum is 47.

The spelling of 18131239388 in words is "eighteen billion, one hundred thirty-one million, two hundred thirty-nine thousand, three hundred eighty-eight".