28689391 has 2 divisors, whose sum is σ = 28689392. Its totient is φ = 28689390.

The previous prime is 28689379. The next prime is 28689407. The reversal of 28689391 is 19398682.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28689391 - 2⁵ = 28689359 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28689341) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14344695 + 14344696.

It is an arithmetic number, because the mean of its divisors is an integer number (14344696).

Almost surely, 2^28689391 is an apocalyptic number.

28689391 is a deficient number, since it is larger than the sum of its proper divisors (1).

28689391 is an equidigital number, since it uses as much as digits as its factorization.

28689391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 186624, while the sum is 46.

The square root of 28689391 is about 5356.2478471408. The cubic root of 28689391 is about 306.1308587791.

The spelling of 28689391 in words is "twenty-eight million, six hundred eighty-nine thousand, three hundred ninety-one".