28765428 has 72 divisors (see below), whose sum is σ = 73749312. Its totient is φ = 8695296.

The previous prime is 28765421. The next prime is 28765453. The reversal of 28765428 is 82456782.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 28765428.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28765421) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 279225 + ... + 279327.

It is an arithmetic number, because the mean of its divisors is an integer number (1024296).

Almost surely, 2^28765428 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 28765428, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36874656).

28765428 is an abundant number, since it is smaller than the sum of its proper divisors (44983884).

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

28765428 is a wasteful number, since it uses less digits than its factorization.

28765428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 201 (or 162 counting only the distinct ones).

The product of its digits is 215040, while the sum is 42.

The square root of 28765428 is about 5363.3411228450. The cubic root of 28765428 is about 306.4010717649.

The spelling of 28765428 in words is "twenty-eight million, seven hundred sixty-five thousand, four hundred twenty-eight".