28021139 has 2 divisors, whose sum is σ = 28021140. Its totient is φ = 28021138.

The previous prime is 28021121. The next prime is 28021141. The reversal of 28021139 is 93112082.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 28021139 - 2¹² = 28017043 is a prime.

Together with 28021141, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (28021109) 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, 14010569 + 14010570.

It is an arithmetic number, because the mean of its divisors is an integer number (14010570).

Almost surely, 2^28021139 is an apocalyptic number.

28021139 is a deficient number, since it is larger than the sum of its proper divisors (1).

28021139 is an equidigital number, since it uses as much as digits as its factorization.

28021139 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 28021139 is about 5293.4996930197. The cubic root of 28021139 is about 303.7352951723.

The spelling of 28021139 in words is "twenty-eight million, twenty-one thousand, one hundred thirty-nine".