28128438 has 64 divisors (see below), whose sum is σ = 71305920. Its totient is φ = 8142336.

The previous prime is 28128391. The next prime is 28128449. The reversal of 28128438 is 83482182.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10756 + ... + 13112.

It is an arithmetic number, because the mean of its divisors is an integer number (1114155).

Almost surely, 2^28128438 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28128438, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35652960).

28128438 is an abundant number, since it is smaller than the sum of its proper divisors (43177482).

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

28128438 is a wasteful number, since it uses less digits than its factorization.

28128438 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2398 (or 2392 counting only the distinct ones).

The product of its digits is 24576, while the sum is 36.

The square root of 28128438 is about 5303.6249867426. The cubic root of 28128438 is about 304.1224907467.

The spelling of 28128438 in words is "twenty-eight million, one hundred twenty-eight thousand, four hundred thirty-eight".