81000018000028 has 12 divisors (see below), whose sum is σ = 141750098411152. Its totient is φ = 40499989882560.

The previous prime is 81000017999947. The next prime is 81000018000029. The reversal of 81000018000028 is 82000081000018.

It is a super-2 number, since 2×81000018000028² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81000018000029) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9482473 + ... + 15871903.

Almost surely, 2^{81000018000028} is an apocalyptic number.

It is an amenable number.

81000018000028 is a deficient number, since it is larger than the sum of its proper divisors (60750080411124).

81000018000028 is a wasteful number, since it uses less digits than its factorization.

81000018000028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9558732 (or 9558730 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 28.

The spelling of 81000018000028 in words is "eighty-one trillion, eighteen million, twenty-eight", and thus it is an aban number and an uban number.