18180953881 has 4 divisors (see below), whose sum is σ = 18184087332. Its totient is φ = 18177820432.

The previous prime is 18180953867. The next prime is 18180953891. The reversal of 18180953881 is 18835908181.

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 10263513481 + 7917440400 = 101309^2 + 88980^2 .

It is a cyclic number.

It is not a de Polignac number, because 18180953881 - 2⁵ = 18180953849 is a prime.

It is a super-2 number, since 2×18180953881² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18180953801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1558006 + ... + 1569631.

It is an arithmetic number, because the mean of its divisors is an integer number (4546021833).

Almost surely, 2^18180953881 is an apocalyptic number.

It is an amenable number.

18180953881 is a deficient number, since it is larger than the sum of its proper divisors (3133451).

18180953881 is an equidigital number, since it uses as much as digits as its factorization.

18180953881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3133450.

The product of its (nonzero) digits is 552960, while the sum is 52.

The spelling of 18180953881 in words is "eighteen billion, one hundred eighty million, nine hundred fifty-three thousand, eight hundred eighty-one".