28993904 has 20 divisors (see below), whose sum is σ = 56328240. Its totient is φ = 14457600.

The previous prime is 28993901. The next prime is 28993927. The reversal of 28993904 is 40939982.

It is a super-2 number, since 2×28993904² = 1681292938322432, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28993901) by changing a digit.

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, 4157 + ... + 8675.

It is an arithmetic number, because the mean of its divisors is an integer number (2816412).

Almost surely, 2^28993904 is an apocalyptic number.

It is an amenable number.

28993904 is a deficient number, since it is larger than the sum of its proper divisors (27334336).

28993904 is a wasteful number, since it uses less digits than its factorization.

28993904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4928 (or 4922 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 44.

The square root of 28993904 is about 5384.5987779964. The cubic root of 28993904 is about 307.2101536538.

The spelling of 28993904 in words is "twenty-eight million, nine hundred ninety-three thousand, nine hundred four".