28328730 has 64 divisors (see below), whose sum is σ = 71221248. Its totient is φ = 7202880.

The previous prime is 28328693. The next prime is 28328731. The reversal of 28328730 is 3782382.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 28328691 and 28328700.

It is not an unprimeable number, because it can be changed into a prime (28328731) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 77007 + ... + 77373.

It is an arithmetic number, because the mean of its divisors is an integer number (1112832).

Almost surely, 2^28328730 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28328730, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35610624).

28328730 is an abundant number, since it is smaller than the sum of its proper divisors (42892518).

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

28328730 is a wasteful number, since it uses less digits than its factorization.

28328730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 491.

The product of its (nonzero) digits is 16128, while the sum is 33.

The square root of 28328730 is about 5322.4740487860. The cubic root of 28328730 is about 304.8426313501.

The spelling of 28328730 in words is "twenty-eight million, three hundred twenty-eight thousand, seven hundred thirty".