18555855581 has 8 divisors (see below), whose sum is σ = 19198771200. Its totient is φ = 17913143920.

The previous prime is 18555855541. The next prime is 18555855583.

18555855581 is nontrivially palindromic in base 10.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18555855581 - 2⁶ = 18555855517 is a prime.

It is a super-2 number, since 2×18555855581² (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 (18555855583) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 147236 + ... + 242466.

It is an arithmetic number, because the mean of its divisors is an integer number (2399846400).

Almost surely, 2^18555855581 is an apocalyptic number.

It is an amenable number.

18555855581 is a deficient number, since it is larger than the sum of its proper divisors (642915619).

18555855581 is an equidigital number, since it uses as much as digits as its factorization.

18555855581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101979.

The product of its digits is 8000000, while the sum is 56.

The spelling of 18555855581 in words is "eighteen billion, five hundred fifty-five million, eight hundred fifty-five thousand, five hundred eighty-one".