18243594431 has 4 divisors (see below), whose sum is σ = 18248770512. Its totient is φ = 18238418352.

The previous prime is 18243594373. The next prime is 18243594449. The reversal of 18243594431 is 13449534281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13449534281 = 43 ⋅312779867.

It is a cyclic number.

It is not a de Polignac number, because 18243594431 - 2⁶ = 18243594367 is a prime.

It is a super-2 number, since 2×18243594431² (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 (18243594331) 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, 2582750 + ... + 2589803.

It is an arithmetic number, because the mean of its divisors is an integer number (4562192628).

Almost surely, 2^18243594431 is an apocalyptic number.

18243594431 is a deficient number, since it is larger than the sum of its proper divisors (5176081).

18243594431 is an equidigital number, since it uses as much as digits as its factorization.

18243594431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5176080.

The product of its digits is 414720, while the sum is 44.

The spelling of 18243594431 in words is "eighteen billion, two hundred forty-three million, five hundred ninety-four thousand, four hundred thirty-one".