28155904 has 56 divisors (see below), whose sum is σ = 64483488. Its totient is φ = 12042240.

The previous prime is 28155901. The next prime is 28155917. The reversal of 28155904 is 40955182.

It is a tau number, because it is divible by the number of its divisors (56).

It is a self number, because there is not a number n which added to its sum of digits gives 28155904.

It is not an unprimeable number, because it can be changed into a prime (28155901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 57099 + ... + 57589.

Almost surely, 2^28155904 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28155904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32241744).

28155904 is an abundant number, since it is smaller than the sum of its proper divisors (36327584).

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

28155904 is an frugal number, since it uses more digits than its factorization.

28155904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 524 (or 500 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 34.

The square root of 28155904 is about 5306.2137160126. The cubic root of 28155904 is about 304.2214452998.

The spelling of 28155904 in words is "twenty-eight million, one hundred fifty-five thousand, nine hundred four".