28657557 has 10 divisors (see below), whose sum is σ = 42809558. Its totient is φ = 19104984.

The previous prime is 28657543. The next prime is 28657561. The reversal of 28657557 is 75575682.

28657557 is a `hidden beast` number, since 28 + 6 + 575 + 57 = 666.

It can be written as a sum of positive squares in only one way, i.e., 28579716 + 77841 = 5346^2 + 279^2 .

It is not a de Polignac number, because 28657557 - 2¹⁸ = 28395413 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 (28657457) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 176818 + ... + 176979.

Almost surely, 2^28657557 is an apocalyptic number.

28657557 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

28657557 is a deficient number, since it is larger than the sum of its proper divisors (14152001).

28657557 is an equidigital number, since it uses as much as digits as its factorization.

28657557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 353809 (or 353800 counting only the distinct ones).

The product of its digits is 588000, while the sum is 45.

The square root of 28657557 is about 5353.2753525295. The cubic root of 28657557 is about 306.0175883777.

The spelling of 28657557 in words is "twenty-eight million, six hundred fifty-seven thousand, five hundred fifty-seven".