28601591 has 4 divisors (see below), whose sum is σ = 28668384. Its totient is φ = 28534800.

The previous prime is 28601567. The next prime is 28601603. The reversal of 28601591 is 19510682.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28601591 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 (28601791) 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, 32750 + ... + 33611.

It is an arithmetic number, because the mean of its divisors is an integer number (7167096).

Almost surely, 2^28601591 is an apocalyptic number.

28601591 is a deficient number, since it is larger than the sum of its proper divisors (66793).

28601591 is an equidigital number, since it uses as much as digits as its factorization.

28601591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66792.

The product of its (nonzero) digits is 4320, while the sum is 32.

The square root of 28601591 is about 5348.0455308458. The cubic root of 28601591 is about 305.8182489687.

Subtracting from 28601591 its reverse (19510682), we obtain a palindrome (9090909).

It can be divided in two parts, 28601 and 591, that added together give a palindrome (29192).

The spelling of 28601591 in words is "twenty-eight million, six hundred one thousand, five hundred ninety-one".