28091904 has 40 divisors (see below), whose sum is σ = 74842680. Its totient is φ = 9363456.

The previous prime is 28091897. The next prime is 28091927. The reversal of 28091904 is 40919082.

It is a hoax number, since the sum of its digits (33) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7609 + ... + 10680.

It is an arithmetic number, because the mean of its divisors is an integer number (1871067).

Almost surely, 2^28091904 is an apocalyptic number.

28091904 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

28091904 is an abundant number, since it is smaller than the sum of its proper divisors (46750776).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28091904 is an equidigital number, since it uses as much as digits as its factorization.

28091904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18310 (or 18294 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 28091904 is about 5300.1796195978. The cubic root of 28091904 is about 303.9907661092.

The spelling of 28091904 in words is "twenty-eight million, ninety-one thousand, nine hundred four".