81005908 has 24 divisors (see below), whose sum is σ = 149026752. Its totient is φ = 38453184.

The previous prime is 81005861. The next prime is 81005917. The reversal of 81005908 is 80950018.

It is a self number, because there is not a number n which added to its sum of digits gives 81005908.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9391 + ... + 15817.

It is an arithmetic number, because the mean of its divisors is an integer number (6209448).

Almost surely, 2^81005908 is an apocalyptic number.

It is an amenable number.

81005908 is a deficient number, since it is larger than the sum of its proper divisors (68020844).

81005908 is a wasteful number, since it uses less digits than its factorization.

81005908 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6591 (or 6589 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 31.

The square root of 81005908 is about 9000.3282162375. The cubic root of 81005908 is about 432.6853903556.

The spelling of 81005908 in words is "eighty-one million, five thousand, nine hundred eight".