81665106 has 16 divisors (see below), whose sum is σ = 164187648. Its totient is φ = 27078800.

The previous prime is 81665083. The next prime is 81665107. The reversal of 81665106 is 60156618.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (81665107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34485 + ... + 36776.

It is an arithmetic number, because the mean of its divisors is an integer number (10261728).

Almost surely, 2^81665106 is an apocalyptic number.

81665106 is an abundant number, since it is smaller than the sum of its proper divisors (82522542).

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

81665106 is a wasteful number, since it uses less digits than its factorization.

81665106 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71457.

The product of its (nonzero) digits is 8640, while the sum is 33.

The square root of 81665106 is about 9036.8747916523. The cubic root of 81665106 is about 433.8559022419.

The spelling of 81665106 in words is "eighty-one million, six hundred sixty-five thousand, one hundred six".