18918442331 has 4 divisors (see below), whose sum is σ = 18933235200. Its totient is φ = 18903649464.

The previous prime is 18918442327. The next prime is 18918442363. The reversal of 18918442331 is 13324481981.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13324481981 = 643 ⋅20722367.

It is a cyclic number.

It is not a de Polignac number, because 18918442331 - 2² = 18918442327 is a prime.

It is a super-2 number, since 2×18918442331² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18918402331) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7394516 + ... + 7397073.

It is an arithmetic number, because the mean of its divisors is an integer number (4733308800).

Almost surely, 2^18918442331 is an apocalyptic number.

18918442331 is a deficient number, since it is larger than the sum of its proper divisors (14792869).

18918442331 is a wasteful number, since it uses less digits than its factorization.

18918442331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14792868.

The product of its digits is 165888, while the sum is 44.

The spelling of 18918442331 in words is "eighteen billion, nine hundred eighteen million, four hundred forty-two thousand, three hundred thirty-one".