18331122381 has 32 divisors (see below), whose sum is σ = 28924172928. Its totient is φ = 10180285440.

The previous prime is 18331122379. The next prime is 18331122409. The reversal of 18331122381 is 18322113381.

It is a happy number.

It is not a de Polignac number, because 18331122381 - 2¹ = 18331122379 is a prime.

It is a super-2 number, since 2×18331122381² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18331122781) 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, 97176 + ... + 214721.

It is an arithmetic number, because the mean of its divisors is an integer number (903880404).

Almost surely, 2^18331122381 is an apocalyptic number.

18331122381 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18331122381 is a deficient number, since it is larger than the sum of its proper divisors (10593050547).

18331122381 is a wasteful number, since it uses less digits than its factorization.

18331122381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 312061.

The product of its digits is 6912, while the sum is 33.

The spelling of 18331122381 in words is "eighteen billion, three hundred thirty-one million, one hundred twenty-two thousand, three hundred eighty-one".