81069904 has 10 divisors (see below), whose sum is σ = 157072970. Its totient is φ = 40534944.

The previous prime is 81069899. The next prime is 81069907. The reversal of 81069904 is 40996018.

It can be written as a sum of positive squares in only one way, i.e., 60093504 + 20976400 = 7752^2 + 4580^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81069907) by changing a digit.

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 as a sum of consecutive naturals, namely, 2533419 + ... + 2533450.

It is an arithmetic number, because the mean of its divisors is an integer number (15707297).

Almost surely, 2^81069904 is an apocalyptic number.

It is an amenable number.

81069904 is a deficient number, since it is larger than the sum of its proper divisors (76003066).

81069904 is a wasteful number, since it uses less digits than its factorization.

81069904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5066877 (or 5066871 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 37.

The square root of 81069904 is about 9003.8827180278. The cubic root of 81069904 is about 432.7993032221.

The spelling of 81069904 in words is "eighty-one million, sixty-nine thousand, nine hundred four".