257557 has 4 divisors (see below), whose sum is σ = 264556. Its totient is φ = 250560.

The previous prime is 257539. The next prime is 257561. The reversal of 257557 is 755752.

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

It can be written as a sum of positive squares in 2 ways, for example, as 217156 + 40401 = 466^2 + 201^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-257557 is a prime.

It is the 508-th Hogben number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (257657) by changing a digit.

It is a nontrivial repunit in base 507.

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, 3444 + ... + 3517.

It is an arithmetic number, because the mean of its divisors is an integer number (66139).

2²⁵⁷⁵⁵⁷ is an apocalyptic number.

It is an amenable number.

257557 is a deficient number, since it is larger than the sum of its proper divisors (6999).

257557 is an equidigital number, since it uses as much as digits as its factorization.

257557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6998.

The product of its digits is 12250, while the sum is 31.

The square root of 257557 is about 507.5007389157. The cubic root of 257557 is about 63.6245102845.

The spelling of 257557 in words is "two hundred fifty-seven thousand, five hundred fifty-seven".