18399395431 has 4 divisors (see below), whose sum is σ = 18827288392. Its totient is φ = 17971502472.

The previous prime is 18399395423. The next prime is 18399395447. The reversal of 18399395431 is 13459399381.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 18399395431 - 2³ = 18399395423 is a prime.

It is a super-2 number, since 2×18399395431² (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 (18399395401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 213946416 + ... + 213946501.

It is an arithmetic number, because the mean of its divisors is an integer number (4706822098).

Almost surely, 2^18399395431 is an apocalyptic number.

18399395431 is a deficient number, since it is larger than the sum of its proper divisors (427892961).

18399395431 is an equidigital number, since it uses as much as digits as its factorization.

18399395431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 427892960.

The product of its digits is 3149280, while the sum is 55.

The spelling of 18399395431 in words is "eighteen billion, three hundred ninety-nine million, three hundred ninety-five thousand, four hundred thirty-one".