81166164 has 12 divisors (see below), whose sum is σ = 189387744. Its totient is φ = 27055384.

The previous prime is 81166147. The next prime is 81166171. The reversal of 81166164 is 46166118.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3381912 + ... + 3381935.

It is an arithmetic number, because the mean of its divisors is an integer number (15782312).

Almost surely, 2^81166164 is an apocalyptic number.

It is an amenable number.

81166164 is an abundant number, since it is smaller than the sum of its proper divisors (108221580).

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

81166164 is a wasteful number, since it uses less digits than its factorization.

81166164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6763854 (or 6763852 counting only the distinct ones).

The product of its digits is 6912, while the sum is 33.

The square root of 81166164 is about 9009.2266038767. The cubic root of 81166164 is about 432.9705331550.

The spelling of 81166164 in words is "eighty-one million, one hundred sixty-six thousand, one hundred sixty-four".