81138166 has 8 divisors (see below), whose sum is σ = 121804704. Its totient is φ = 40536600.

The previous prime is 81138149. The next prime is 81138179. The reversal of 81138166 is 66183118.

It is a sphenic number, since it is the product of 3 distinct primes.

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, 12990 + ... + 18193.

It is an arithmetic number, because the mean of its divisors is an integer number (15225588).

Almost surely, 2^81138166 is an apocalyptic number.

81138166 is a deficient number, since it is larger than the sum of its proper divisors (40666538).

81138166 is a wasteful number, since it uses less digits than its factorization.

81138166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32486.

The product of its digits is 6912, while the sum is 34.

The square root of 81138166 is about 9007.6726183848. The cubic root of 81138166 is about 432.9207435116.

The spelling of 81138166 in words is "eighty-one million, one hundred thirty-eight thousand, one hundred sixty-six".