18815731081 has 8 divisors (see below), whose sum is σ = 21506201024. Its totient is φ = 16125888240.

The previous prime is 18815731061. The next prime is 18815731159. The reversal of 18815731081 is 18013751881.

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

It is not a de Polignac number, because 18815731081 - 2⁹ = 18815730569 is a prime.

It is a super-2 number, since 2×18815731081² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18815731001) 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, 90615 + ... + 214108.

It is an arithmetic number, because the mean of its divisors is an integer number (2688275128).

Almost surely, 2^18815731081 is an apocalyptic number.

It is an amenable number.

18815731081 is a deficient number, since it is larger than the sum of its proper divisors (2690469943).

18815731081 is an equidigital number, since it uses as much as digits as its factorization.

18815731081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 313551.

The product of its (nonzero) digits is 53760, while the sum is 43.

The spelling of 18815731081 in words is "eighteen billion, eight hundred fifteen million, seven hundred thirty-one thousand, eighty-one".