28191139 has 2 divisors, whose sum is σ = 28191140. Its totient is φ = 28191138.

The previous prime is 28191133. The next prime is 28191167. The reversal of 28191139 is 93119182.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28191139 - 2⁷ = 28191011 is a prime.

It is not a weakly prime, because it can be changed into another prime (28191133) 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 as a sum of consecutive naturals, namely, 14095569 + 14095570.

It is an arithmetic number, because the mean of its divisors is an integer number (14095570).

Almost surely, 2^28191139 is an apocalyptic number.

28191139 is a deficient number, since it is larger than the sum of its proper divisors (1).

28191139 is an equidigital number, since it uses as much as digits as its factorization.

28191139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3888, while the sum is 34.

The square root of 28191139 is about 5309.5328419740. The cubic root of 28191139 is about 304.3482958328.

The spelling of 28191139 in words is "twenty-eight million, one hundred ninety-one thousand, one hundred thirty-nine".