28530 has 24 divisors (see below), whose sum is σ = 74412. Its totient is φ = 7584.

The previous prime is 28517. The next prime is 28537. The reversal of 28530 is 3582.

It can be written as a sum of positive squares in 2 ways, for example, as 25281 + 3249 = 159^2 + 57^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nialpdrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (28537) by changing a digit.

28530 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 69 + ... + 248.

2²⁸⁵³⁰ is an apocalyptic number.

28530 is an abundant number, since it is smaller than the sum of its proper divisors (45882).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37206).

28530 is a wasteful number, since it uses less digits than its factorization.

28530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 330 (or 327 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 28530 is about 168.9082591231. The cubic root of 28530 is about 30.5562877082.

The spelling of 28530 in words is "twenty-eight thousand, five hundred thirty".