28189907 has 4 divisors (see below), whose sum is σ = 28448640. Its totient is φ = 27931176.

The previous prime is 28189891. The next prime is 28189921. The reversal of 28189907 is 70998182.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 70998182 = 2 ⋅35499091.

It is a cyclic number.

It is not a de Polignac number, because 28189907 - 2⁴ = 28189891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28189307) 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 3 ways as a sum of consecutive naturals, for example, 129203 + ... + 129420.

It is an arithmetic number, because the mean of its divisors is an integer number (7112160).

Almost surely, 2^28189907 is an apocalyptic number.

28189907 is a deficient number, since it is larger than the sum of its proper divisors (258733).

28189907 is a wasteful number, since it uses less digits than its factorization.

28189907 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 258732.

The product of its (nonzero) digits is 72576, while the sum is 44.

The square root of 28189907 is about 5309.4168229665. The cubic root of 28189907 is about 304.3438622580.

The spelling of 28189907 in words is "twenty-eight million, one hundred eighty-nine thousand, nine hundred seven".