18086557981 has 4 divisors (see below), whose sum is σ = 18087432832. Its totient is φ = 18085683132.

The previous prime is 18086557969. The next prime is 18086557991. The reversal of 18086557981 is 18975568081.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 18086557981 - 2⁵ = 18086557949 is a prime.

It is a super-2 number, since 2×18086557981² (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 (18086557991) 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, 405645 + ... + 448018.

It is an arithmetic number, because the mean of its divisors is an integer number (4521858208).

Almost surely, 2^18086557981 is an apocalyptic number.

It is an amenable number.

18086557981 is a deficient number, since it is larger than the sum of its proper divisors (874851).

18086557981 is an equidigital number, since it uses as much as digits as its factorization.

18086557981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 874850.

The product of its (nonzero) digits is 4838400, while the sum is 58.

The spelling of 18086557981 in words is "eighteen billion, eighty-six million, five hundred fifty-seven thousand, nine hundred eighty-one".