18538791431 has 32 divisors (see below), whose sum is σ = 20240539200. Its totient is φ = 16915931136.

The previous prime is 18538791391. The next prime is 18538791433. The reversal of 18538791431 is 13419783581.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 18538791431 - 2³⁴ = 1358922247 is a prime.

It is a super-2 number, since 2×18538791431² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18538791431.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18538791433) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19784795 + ... + 19785731.

It is an arithmetic number, because the mean of its divisors is an integer number (632516850).

Almost surely, 2^18538791431 is an apocalyptic number.

18538791431 is a deficient number, since it is larger than the sum of its proper divisors (1701747769).

18538791431 is a wasteful number, since it uses less digits than its factorization.

18538791431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1283.

The product of its digits is 725760, while the sum is 50.

The spelling of 18538791431 in words is "eighteen billion, five hundred thirty-eight million, seven hundred ninety-one thousand, four hundred thirty-one".