28290991 has 2 divisors, whose sum is σ = 28290992. Its totient is φ = 28290990.

The previous prime is 28290967. The next prime is 28291013. The reversal of 28290991 is 19909282.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 28290991 - 2¹¹ = 28288943 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28290961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14145495 + 14145496.

It is an arithmetic number, because the mean of its divisors is an integer number (14145496).

Almost surely, 2^28290991 is an apocalyptic number.

28290991 is a deficient number, since it is larger than the sum of its proper divisors (1).

28290991 is an equidigital number, since it uses as much as digits as its factorization.

28290991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23328, while the sum is 40.

The square root of 28290991 is about 5318.9276174808. The cubic root of 28290991 is about 304.7072026584.

The spelling of 28290991 in words is "twenty-eight million, two hundred ninety thousand, nine hundred ninety-one".