81084904 has 8 divisors (see below), whose sum is σ = 152034210. Its totient is φ = 40542448.

The previous prime is 81084901. The next prime is 81084929. The reversal of 81084904 is 40948018.

It can be written as a sum of positive squares in only one way, i.e., 49702500 + 31382404 = 7050^2 + 5602^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a self number, because there is not a number n which added to its sum of digits gives 81084904.

It is not an unprimeable number, because it can be changed into a prime (81084901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5067799 + ... + 5067814.

Almost surely, 2^81084904 is an apocalyptic number.

It is an amenable number.

81084904 is a deficient number, since it is larger than the sum of its proper divisors (70949306).

81084904 is a wasteful number, since it uses less digits than its factorization.

81084904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10135619 (or 10135615 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 34.

The square root of 81084904 is about 9004.7156534785. The cubic root of 81084904 is about 432.8259945460.

The spelling of 81084904 in words is "eighty-one million, eighty-four thousand, nine hundred four".