81093904 has 20 divisors (see below), whose sum is σ = 157378320. Its totient is φ = 40480160.

The previous prime is 81093877. The next prime is 81093911. The reversal of 81093904 is 40939018.

It is a super-2 number, since 2×81093904² = 13152442531922432, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81093904.

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 3 ways as a sum of consecutive naturals, for example, 6699 + ... + 14389.

It is an arithmetic number, because the mean of its divisors is an integer number (7868916).

Almost surely, 2^81093904 is an apocalyptic number.

It is an amenable number.

81093904 is a deficient number, since it is larger than the sum of its proper divisors (76284416).

81093904 is a wasteful number, since it uses less digits than its factorization.

81093904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8358 (or 8352 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 81093904 is about 9005.2153777686. The cubic root of 81093904 is about 432.8420077603.

The spelling of 81093904 in words is "eighty-one million, ninety-three thousand, nine hundred four".