81016566 has 16 divisors (see below), whose sum is σ = 162316224. Its totient is φ = 26958344.

The previous prime is 81016541. The next prime is 81016571. The reversal of 81016566 is 66561018.

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 a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7980 + ... + 15023.

It is an arithmetic number, because the mean of its divisors is an integer number (10144764).

Almost surely, 2^81016566 is an apocalyptic number.

81016566 is an abundant number, since it is smaller than the sum of its proper divisors (81299658).

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

81016566 is a wasteful number, since it uses less digits than its factorization.

81016566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23595.

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

The square root of 81016566 is about 9000.9202862818. The cubic root of 81016566 is about 432.7043657561.

The spelling of 81016566 in words is "eighty-one million, sixteen thousand, five hundred sixty-six".