28031328 has 72 divisors (see below), whose sum is σ = 85857408. Its totient is φ = 8623872.

The previous prime is 28031321. The next prime is 28031369. The reversal of 28031328 is 82313082.

28031328 is a nontrivial binomial coefficient, being equal to C(7488, 2).

It is a tau number, because it is divible by the number of its divisors (72).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28031321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1 + ... + 7487.

It is an arithmetic number, because the mean of its divisors is an integer number (1192464).

Almost surely, 2^28031328 is an apocalyptic number.

28031328 is the 7487-th triangular number and also the 3744-th hexagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28031328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42928704).

28031328 is an abundant number, since it is smaller than the sum of its proper divisors (57826080).

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

28031328 is a wasteful number, since it uses less digits than its factorization.

28031328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7516 (or 7505 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 28031328 is about 5294.4620123295. The cubic root of 28031328 is about 303.7721052855.

The spelling of 28031328 in words is "twenty-eight million, thirty-one thousand, three hundred twenty-eight".