28189871 has 4 divisors (see below), whose sum is σ = 28529592. Its totient is φ = 27850152.

The previous prime is 28189867. The next prime is 28189873. The reversal of 28189871 is 17898182.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 28189871 - 2² = 28189867 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 (28189873) 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, 169736 + ... + 169901.

It is an arithmetic number, because the mean of its divisors is an integer number (7132398).

Almost surely, 2^28189871 is an apocalyptic number.

28189871 is a deficient number, since it is larger than the sum of its proper divisors (339721).

28189871 is an equidigital number, since it uses as much as digits as its factorization.

28189871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 339720.

The product of its digits is 64512, while the sum is 44.

The square root of 28189871 is about 5309.4134327626. The cubic root of 28189871 is about 304.3437327036.

The spelling of 28189871 in words is "twenty-eight million, one hundred eighty-nine thousand, eight hundred seventy-one".