28878928 has 20 divisors (see below), whose sum is σ = 60257428. Its totient is φ = 13328640.

The previous prime is 28878923. The next prime is 28878931. The reversal of 28878928 is 82987882.

It can be written as a sum of positive squares in 2 ways, for example, as 3356224 + 25522704 = 1832^2 + 5052^2 .

It is a Harshad number since it is a multiple of its sum of digits (52).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28878923) 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, 69213 + ... + 69628.

Almost surely, 2^28878928 is an apocalyptic number.

It is an amenable number.

28878928 is an abundant number, since it is smaller than the sum of its proper divisors (31378500).

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

28878928 is a wasteful number, since it uses less digits than its factorization.

28878928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138862 (or 138856 counting only the distinct ones).

The product of its digits is 1032192, while the sum is 52.

The square root of 28878928 is about 5373.9117968199. The cubic root of 28878928 is about 306.8035326901.

The spelling of 28878928 in words is "twenty-eight million, eight hundred seventy-eight thousand, nine hundred twenty-eight".