28991135 has 4 divisors (see below), whose sum is σ = 34789368. Its totient is φ = 23192904.

The previous prime is 28991129. The next prime is 28991161. The reversal of 28991135 is 53119982.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28991135 - 2⁶ = 28991071 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 2899109 + ... + 2899118.

It is an arithmetic number, because the mean of its divisors is an integer number (8697342).

Almost surely, 2^28991135 is an apocalyptic number.

28991135 is a deficient number, since it is larger than the sum of its proper divisors (5798233).

28991135 is an equidigital number, since it uses as much as digits as its factorization.

28991135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5798232.

The product of its digits is 19440, while the sum is 38.

The square root of 28991135 is about 5384.3416496355. The cubic root of 28991135 is about 307.2003735291.

The spelling of 28991135 in words is "twenty-eight million, nine hundred ninety-one thousand, one hundred thirty-five".