8181904 has 20 divisors (see below), whose sum is σ = 15919740. Its totient is φ = 4073600.

The previous prime is 8181893. The next prime is 8181917. The reversal of 8181904 is 4091818.

It can be written as a sum of positive squares in 2 ways, for example, as 608400 + 7573504 = 780^2 + 2752^2 .

It is an Ulam 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 3 ways as a sum of consecutive naturals, for example, 3354 + ... + 5254.

It is an arithmetic number, because the mean of its divisors is an integer number (795987).

Almost surely, 2^8181904 is an apocalyptic number.

It is an amenable number.

8181904 is a deficient number, since it is larger than the sum of its proper divisors (7737836).

8181904 is a wasteful number, since it uses less digits than its factorization.

8181904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2178 (or 2172 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 31.

The square root of 8181904 is about 2860.4027688422. The cubic root of 8181904 is about 201.5045203788.

Subtracting from 8181904 its product of nonzero digits (2304), we obtain a square (8179600 = 2860²).

The spelling of 8181904 in words is "eight million, one hundred eighty-one thousand, nine hundred four".