28124191 has 4 divisors (see below), whose sum is σ = 28220472. Its totient is φ = 28027912.

The previous prime is 28124167. The next prime is 28124209. The reversal of 28124191 is 19142182.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19142182 = 2 ⋅9571091.

It is a cyclic number.

It is not a de Polignac number, because 28124191 - 2⁹ = 28123679 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 (28124891) 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, 47701 + ... + 48286.

It is an arithmetic number, because the mean of its divisors is an integer number (7055118).

Almost surely, 2^28124191 is an apocalyptic number.

28124191 is a deficient number, since it is larger than the sum of its proper divisors (96281).

28124191 is an equidigital number, since it uses as much as digits as its factorization.

28124191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96280.

The product of its digits is 1152, while the sum is 28.

The square root of 28124191 is about 5303.2245850991. The cubic root of 28124191 is about 304.1071838980.

Subtracting from 28124191 its reverse (19142182), we obtain a square (8982009 = 2997²).

The spelling of 28124191 in words is "twenty-eight million, one hundred twenty-four thousand, one hundred ninety-one".