28715591 has 4 divisors (see below), whose sum is σ = 28789800. Its totient is φ = 28641384.

The previous prime is 28715587. The next prime is 28715627. The reversal of 28715591 is 19551782.

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 28715591 - 2² = 28715587 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 (28715551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36521 + ... + 37298.

It is an arithmetic number, because the mean of its divisors is an integer number (7197450).

Almost surely, 2^28715591 is an apocalyptic number.

28715591 is a deficient number, since it is larger than the sum of its proper divisors (74209).

28715591 is an equidigital number, since it uses as much as digits as its factorization.

28715591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74208.

The product of its digits is 25200, while the sum is 38.

The square root of 28715591 is about 5358.6930309545. The cubic root of 28715591 is about 306.2240196758.

The spelling of 28715591 in words is "twenty-eight million, seven hundred fifteen thousand, five hundred ninety-one".