28257587 has 4 divisors (see below), whose sum is σ = 29919816. Its totient is φ = 26595360.

The previous prime is 28257583. The next prime is 28257611. The reversal of 28257587 is 78575282.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78575282 = 2 ⋅39287641.

It is a cyclic number.

It is not a de Polignac number, because 28257587 - 2² = 28257583 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28257583) 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, 831089 + ... + 831122.

It is an arithmetic number, because the mean of its divisors is an integer number (7479954).

Almost surely, 2^28257587 is an apocalyptic number.

28257587 is a deficient number, since it is larger than the sum of its proper divisors (1662229).

28257587 is a wasteful number, since it uses less digits than its factorization.

28257587 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1662228.

The product of its digits is 313600, while the sum is 44.

The square root of 28257587 is about 5315.7865833760. The cubic root of 28257587 is about 304.5872298607.

The spelling of 28257587 in words is "twenty-eight million, two hundred fifty-seven thousand, five hundred eighty-seven".