28090691 has 4 divisors (see below), whose sum is σ = 28171992. Its totient is φ = 28009392.

The previous prime is 28090687. The next prime is 28090693. The reversal of 28090691 is 19609082.

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 28090691 - 2² = 28090687 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28090693) 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 in 3 ways as a sum of consecutive naturals, for example, 40130 + ... + 40823.

It is an arithmetic number, because the mean of its divisors is an integer number (7042998).

Almost surely, 2^28090691 is an apocalyptic number.

28090691 is a deficient number, since it is larger than the sum of its proper divisors (81301).

28090691 is an equidigital number, since it uses as much as digits as its factorization.

28090691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81300.

The product of its (nonzero) digits is 7776, while the sum is 35.

The square root of 28090691 is about 5300.0651882783. The cubic root of 28090691 is about 303.9863906361.

The spelling of 28090691 in words is "twenty-eight million, ninety thousand, six hundred ninety-one".