28357257 has 4 divisors (see below), whose sum is σ = 37809680. Its totient is φ = 18904836.

The previous prime is 28357243. The next prime is 28357267. The reversal of 28357257 is 75275382.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 28357257 - 2⁶ = 28357193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28357267) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4726207 + ... + 4726212.

It is an arithmetic number, because the mean of its divisors is an integer number (9452420).

Almost surely, 2^28357257 is an apocalyptic number.

It is an amenable number.

28357257 is a deficient number, since it is larger than the sum of its proper divisors (9452423).

28357257 is an equidigital number, since it uses as much as digits as its factorization.

28357257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9452422.

The product of its digits is 117600, while the sum is 39.

The square root of 28357257 is about 5325.1532372318. The cubic root of 28357257 is about 304.9449224204.

The spelling of 28357257 in words is "twenty-eight million, three hundred fifty-seven thousand, two hundred fifty-seven".