81856027185 has 64 divisors (see below), whose sum is σ = 134983860480. Its totient is φ = 42340654080.

The previous prime is 81856027171. The next prime is 81856027189. The reversal of 81856027185 is 58172065818.

It is not a de Polignac number, because 81856027185 - 2⁸ = 81856026929 is a prime.

It is a super-2 number, since 2×81856027185² (a number of 23 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81856027189) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 66603151 + ... + 66604379.

It is an arithmetic number, because the mean of its divisors is an integer number (2109122820).

Almost surely, 2^81856027185 is an apocalyptic number.

It is an amenable number.

81856027185 is a deficient number, since it is larger than the sum of its proper divisors (53127833295).

81856027185 is a wasteful number, since it uses less digits than its factorization.

81856027185 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2258.

The product of its (nonzero) digits is 1075200, while the sum is 51.

The spelling of 81856027185 in words is "eighty-one billion, eight hundred fifty-six million, twenty-seven thousand, one hundred eighty-five".