28432728 has 64 divisors (see below), whose sum is σ = 79632000. Its totient is φ = 9399456.

The previous prime is 28432711. The next prime is 28432739. The reversal of 28432728 is 82723482.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 28432692 and 28432701.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 29551 + ... + 30497.

It is an arithmetic number, because the mean of its divisors is an integer number (1244250).

Almost surely, 2^28432728 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 28432728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39816000).

28432728 is an abundant number, since it is smaller than the sum of its proper divisors (51199272).

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

28432728 is a wasteful number, since it uses less digits than its factorization.

28432728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1101 (or 1091 counting only the distinct ones).

The product of its digits is 43008, while the sum is 36.

The square root of 28432728 is about 5332.2348035322. The cubic root of 28432728 is about 305.2152131515.

The spelling of 28432728 in words is "twenty-eight million, four hundred thirty-two thousand, seven hundred twenty-eight".