81908886 has 32 divisors (see below), whose sum is σ = 173145600. Its totient is φ = 25760160.

The previous prime is 81908881. The next prime is 81908887. The reversal of 81908886 is 68880918.

It is a Smith number, since the sum of its digits (48) 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 not an unprimeable number, because it can be changed into a prime (81908881) 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 15 ways as a sum of consecutive naturals, for example, 29331 + ... + 32001.

It is an arithmetic number, because the mean of its divisors is an integer number (5410800).

Almost surely, 2^81908886 is an apocalyptic number.

81908886 is an abundant number, since it is smaller than the sum of its proper divisors (91236714).

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

81908886 is a wasteful number, since it uses less digits than its factorization.

81908886 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2964.

The product of its (nonzero) digits is 221184, while the sum is 48.

The square root of 81908886 is about 9050.3528108025. The cubic root of 81908886 is about 434.2871771176.

The spelling of 81908886 in words is "eighty-one million, nine hundred eight thousand, eight hundred eighty-six".