81000000000018 has 96 divisors (see below), whose sum is σ = 207660884663232. Its totient is φ = 22538150476800.

The previous prime is 81000000000013. The next prime is 81000000000053.

It is a happy number.

81000000000018 is nontrivially palindromic in base 10.

It is a super-2 number, since 2×81000000000018² (a number of 29 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

81000000000018 is a strobogrammatic number because it is the same when read upside-down.

It is a self number, because there is not a number n which added to its sum of digits gives 81000000000018.

It is not an unprimeable number, because it can be changed into a prime (81000000000013) 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 47 ways as a sum of consecutive naturals, for example, 293327496 + ... + 293603507.

It is an arithmetic number, because the mean of its divisors is an integer number (2163134215242).

Almost surely, 2^{81000000000018} is an apocalyptic number.

81000000000018 is an abundant number, since it is smaller than the sum of its proper divisors (126660884663214).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81000000000018 is a wasteful number, since it uses less digits than its factorization.

81000000000018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 586931080 (or 586931077 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Subtracting from 81000000000018 its sum of digits (18), we obtain a 4-th power (81000000000000 = 3000⁴).

It can be divided in two parts, 810000000000 and 18, that added together give a palindrome (810000000018).

The spelling of 81000000000018 in words is "eighty-one trillion, eighteen", and thus it is an aban number and an uban number.