28765530 has 80 divisors (see below), whose sum is σ = 81936360. Its totient is φ = 7216128.

The previous prime is 28765501. The next prime is 28765537. The reversal of 28765530 is 3556782.

It can be written as a sum of positive squares in 4 ways, for example, as 28483569 + 281961 = 5337^2 + 531^2 .

It is not an unprimeable number, because it can be changed into a prime (28765537) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 12726 + ... + 14814.

Almost surely, 2^28765530 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28765530, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40968180).

28765530 is an abundant number, since it is smaller than the sum of its proper divisors (53170830).

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

28765530 is a wasteful number, since it uses less digits than its factorization.

28765530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2125 (or 2116 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 36.

The square root of 28765530 is about 5363.3506318345. The cubic root of 28765530 is about 306.4014339227.

The spelling of 28765530 in words is "twenty-eight million, seven hundred sixty-five thousand, five hundred thirty".