28728871 has 4 divisors (see below), whose sum is σ = 28739592. Its totient is φ = 28718152.

The previous prime is 28728857. The next prime is 28728881. The reversal of 28728871 is 17882782.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 28728871 - 2²³ = 20340263 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28728851) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2640 + ... + 8026.

It is an arithmetic number, because the mean of its divisors is an integer number (7184898).

Almost surely, 2^28728871 is an apocalyptic number.

28728871 is a deficient number, since it is larger than the sum of its proper divisors (10721).

28728871 is an equidigital number, since it uses as much as digits as its factorization.

28728871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10720.

The product of its digits is 100352, while the sum is 43.

The square root of 28728871 is about 5359.9319958373. The cubic root of 28728871 is about 306.2712185215.

The spelling of 28728871 in words is "twenty-eight million, seven hundred twenty-eight thousand, eight hundred seventy-one".