28717728 has 48 divisors (see below), whose sum is σ = 81186336. Its totient is φ = 8835840.

The previous prime is 28717727. The next prime is 28717729. The reversal of 28717728 is 82771782.

It is an interprime number because it is at equal distance from previous prime (28717727) and next prime (28717729).

It is a tau number, because it is divible by the number of its divisors (48).

It is a self number, because there is not a number n which added to its sum of digits gives 28717728.

It is not an unprimeable number, because it can be changed into a prime (28717727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10258 + ... + 12753.

It is an arithmetic number, because the mean of its divisors is an integer number (1691382).

Almost surely, 2^28717728 is an apocalyptic number.

It is an amenable number.

28717728 is an abundant number, since it is smaller than the sum of its proper divisors (52468608).

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

28717728 is a wasteful number, since it uses less digits than its factorization.

28717728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23037 (or 23029 counting only the distinct ones).

The product of its digits is 87808, while the sum is 42.

The square root of 28717728 is about 5358.8924228799. The cubic root of 28717728 is about 306.2316158338.

The spelling of 28717728 in words is "twenty-eight million, seven hundred seventeen thousand, seven hundred twenty-eight".