81856027166 has 4 divisors (see below), whose sum is σ = 122784040752. Its totient is φ = 40928013582.

The previous prime is 81856027163. The next prime is 81856027171. The reversal of 81856027166 is 66172065818.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81856027163) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20464006790 + ... + 20464006793.

It is an arithmetic number, because the mean of its divisors is an integer number (30696010188).

Almost surely, 2^81856027166 is an apocalyptic number.

81856027166 is a deficient number, since it is larger than the sum of its proper divisors (40928013586).

81856027166 is a wasteful number, since it uses less digits than its factorization.

81856027166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40928013585.

The product of its (nonzero) digits is 967680, while the sum is 50.

The spelling of 81856027166 in words is "eighty-one billion, eight hundred fifty-six million, twenty-seven thousand, one hundred sixty-six".