28821904 has 20 divisors (see below), whose sum is σ = 57032064. Its totient is φ = 14103968.

The previous prime is 28821887. The next prime is 28821931. The reversal of 28821904 is 40912882.

It is a super-3 number, since 3×28821904³ (a number of 23 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 28821904.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18412 + ... + 19915.

Almost surely, 2^28821904 is an apocalyptic number.

It is an amenable number.

28821904 is a deficient number, since it is larger than the sum of its proper divisors (28210160).

28821904 is a wasteful number, since it uses less digits than its factorization.

28821904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38382 (or 38376 counting only the distinct ones).

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

The square root of 28821904 is about 5368.6035428219. The cubic root of 28821904 is about 306.6014627178.

The spelling of 28821904 in words is "twenty-eight million, eight hundred twenty-one thousand, nine hundred four".