28909891 has 2 divisors, whose sum is σ = 28909892. Its totient is φ = 28909890.

The previous prime is 28909861. The next prime is 28909921. The reversal of 28909891 is 19890982.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (28909861) and next prime (28909921).

It is a cyclic number.

It is not a de Polignac number, because 28909891 - 2⁹ = 28909379 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (28909801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14454945 + 14454946.

It is an arithmetic number, because the mean of its divisors is an integer number (14454946).

Almost surely, 2^28909891 is an apocalyptic number.

28909891 is a deficient number, since it is larger than the sum of its proper divisors (1).

28909891 is an equidigital number, since it uses as much as digits as its factorization.

28909891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 93312, while the sum is 46.

The square root of 28909891 is about 5376.7918873618. The cubic root of 28909891 is about 306.9131416152.

The spelling of 28909891 in words is "twenty-eight million, nine hundred nine thousand, eight hundred ninety-one".