18131665881 has 8 divisors (see below), whose sum is σ = 27629205184. Its totient is φ = 10360951920.

The previous prime is 18131665837. The next prime is 18131665891. The reversal of 18131665881 is 18856613181.

It is a happy number.

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

It is not a de Polignac number, because 18131665881 - 2⁶ = 18131665817 is a prime.

It is a super-2 number, since 2×18131665881² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 18131665881.

It is not an unprimeable number, because it can be changed into a prime (18131665801) 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, 431706310 + ... + 431706351.

It is an arithmetic number, because the mean of its divisors is an integer number (3453650648).

Almost surely, 2^18131665881 is an apocalyptic number.

It is an amenable number.

18131665881 is a deficient number, since it is larger than the sum of its proper divisors (9497539303).

18131665881 is an equidigital number, since it uses as much as digits as its factorization.

18131665881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 863412671.

The product of its digits is 276480, while the sum is 48.

The spelling of 18131665881 in words is "eighteen billion, one hundred thirty-one million, six hundred sixty-five thousand, eight hundred eighty-one".