18323557393 has 4 divisors (see below), whose sum is σ = 18363305268. Its totient is φ = 18283809520.

The previous prime is 18323557391. The next prime is 18323557409. The reversal of 18323557393 is 39375532381.

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

It can be written as a sum of positive squares in 2 ways, for example, as 3265322449 + 15058234944 = 57143^2 + 122712^2 .

It is a cyclic number.

It is not a de Polignac number, because 18323557393 - 2¹ = 18323557391 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18323557391) 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, 19873246 + ... + 19874167.

It is an arithmetic number, because the mean of its divisors is an integer number (4590826317).

Almost surely, 2^18323557393 is an apocalyptic number.

It is an amenable number.

18323557393 is a deficient number, since it is larger than the sum of its proper divisors (39747875).

18323557393 is an equidigital number, since it uses as much as digits as its factorization.

18323557393 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39747874.

The product of its digits is 2041200, while the sum is 49.

The spelling of 18323557393 in words is "eighteen billion, three hundred twenty-three million, five hundred fifty-seven thousand, three hundred ninety-three".