28721184 has 24 divisors (see below), whose sum is σ = 75393360. Its totient is φ = 9573696.

The previous prime is 28721171. The next prime is 28721191. The reversal of 28721184 is 48112782.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (24).

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, 149494 + ... + 149685.

It is an arithmetic number, because the mean of its divisors is an integer number (3141390).

Almost surely, 2^28721184 is an apocalyptic number.

28721184 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

28721184 is an abundant number, since it is smaller than the sum of its proper divisors (46672176).

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

28721184 is a wasteful number, since it uses less digits than its factorization.

28721184 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 299192 (or 299184 counting only the distinct ones).

The product of its digits is 7168, while the sum is 33.

The square root of 28721184 is about 5359.2148678701. The cubic root of 28721184 is about 306.2438996980.

The spelling of 28721184 in words is "twenty-eight million, seven hundred twenty-one thousand, one hundred eighty-four".