18405238831 has 12 divisors (see below), whose sum is σ = 21424139472. Its totient is φ = 15765630048.

The previous prime is 18405238829. The next prime is 18405238843. The reversal of 18405238831 is 13883250481.

It is not a de Polignac number, because 18405238831 - 2¹ = 18405238829 is a prime.

It is a super-2 number, since 2×18405238831² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18405238331) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 46110 + ... + 197323.

It is an arithmetic number, because the mean of its divisors is an integer number (1785344956).

Almost surely, 2^18405238831 is an apocalyptic number.

18405238831 is a deficient number, since it is larger than the sum of its proper divisors (3018900641).

18405238831 is a wasteful number, since it uses less digits than its factorization.

18405238831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 244990 (or 244983 counting only the distinct ones).

The product of its (nonzero) digits is 184320, while the sum is 43.

The spelling of 18405238831 in words is "eighteen billion, four hundred five million, two hundred thirty-eight thousand, eight hundred thirty-one".