81311166 has 24 divisors (see below), whose sum is σ = 177794760. Its totient is φ = 26854416.

The previous prime is 81311147. The next prime is 81311177. The reversal of 81311166 is 66111318.

It is a super-2 number, since 2×81311166² = 13223011432559112, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 18760 + ... + 22683.

It is an arithmetic number, because the mean of its divisors is an integer number (7408115).

Almost surely, 2^81311166 is an apocalyptic number.

81311166 is an abundant number, since it is smaller than the sum of its proper divisors (96483594).

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

81311166 is a wasteful number, since it uses less digits than its factorization.

81311166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41560 (or 41557 counting only the distinct ones).

The product of its digits is 864, while the sum is 27.

The square root of 81311166 is about 9017.2704295701. The cubic root of 81311166 is about 433.2282113185.

The spelling of 81311166 in words is "eighty-one million, three hundred eleven thousand, one hundred sixty-six".