28516991 has 2 divisors, whose sum is σ = 28516992. Its totient is φ = 28516990.

The previous prime is 28516979. The next prime is 28517039. The reversal of 28516991 is 19961582.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28516991 - 2¹⁸ = 28254847 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 (28516091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14258495 + 14258496.

It is an arithmetic number, because the mean of its divisors is an integer number (14258496).

Almost surely, 2^28516991 is an apocalyptic number.

28516991 is a deficient number, since it is larger than the sum of its proper divisors (1).

28516991 is an equidigital number, since it uses as much as digits as its factorization.

28516991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 38880, while the sum is 41.

The square root of 28516991 is about 5340.1302418574. The cubic root of 28516991 is about 305.5164268915.

The spelling of 28516991 in words is "twenty-eight million, five hundred sixteen thousand, nine hundred ninety-one".