28568591 has 4 divisors (see below), whose sum is σ = 28580232. Its totient is φ = 28556952.

The previous prime is 28568563. The next prime is 28568593. The reversal of 28568591 is 19586582.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 19586582 = 2 ⋅9793291.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28568591 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28568593) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 545 + ... + 7578.

It is an arithmetic number, because the mean of its divisors is an integer number (7145058).

Almost surely, 2^28568591 is an apocalyptic number.

28568591 is a deficient number, since it is larger than the sum of its proper divisors (11641).

28568591 is an equidigital number, since it uses as much as digits as its factorization.

28568591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11640.

The product of its digits is 172800, while the sum is 44.

The square root of 28568591 is about 5344.9594011554. The cubic root of 28568591 is about 305.7005878448.

Subtracting from 28568591 its reverse (19586582), we obtain a square (8982009 = 2997²).

The spelling of 28568591 in words is "twenty-eight million, five hundred sixty-eight thousand, five hundred ninety-one".