18558909109 has 4 divisors (see below), whose sum is σ = 19986517516. Its totient is φ = 17131300704.

The previous prime is 18558909077. The next prime is 18558909119. The reversal of 18558909109 is 90190985581.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90190985581 = 17 ⋅5305352093.

It can be written as a sum of positive squares in 2 ways, for example, as 10117342225 + 8441566884 = 100585^2 + 91878^2 .

It is a cyclic number.

It is not a de Polignac number, because 18558909109 - 2⁵ = 18558909077 is a prime.

It is a super-2 number, since 2×18558909109² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18558909109.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18558909119) 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, 713804184 + ... + 713804209.

It is an arithmetic number, because the mean of its divisors is an integer number (4996629379).

Almost surely, 2^18558909109 is an apocalyptic number.

It is an amenable number.

18558909109 is a deficient number, since it is larger than the sum of its proper divisors (1427608407).

18558909109 is a wasteful number, since it uses less digits than its factorization.

18558909109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1427608406.

The product of its (nonzero) digits is 1166400, while the sum is 55.

The spelling of 18558909109 in words is "eighteen billion, five hundred fifty-eight million, nine hundred nine thousand, one hundred nine".