257565 has 32 divisors (see below), whose sum is σ = 516096. Its totient is φ = 106560.

The previous prime is 257561. The next prime is 257591. The reversal of 257565 is 565752.

257565 is nontrivially palindromic in base 13.

It is not a de Polignac number, because 257565 - 2² = 257561 is a prime.

257565 is a lucky number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 257565.

It is not an unprimeable number, because it can be changed into a prime (257561) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1044 + ... + 1266.

It is an arithmetic number, because the mean of its divisors is an integer number (16128).

2²⁵⁷⁵⁶⁵ is an apocalyptic number.

It is an amenable number.

257565 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

257565 is a wasteful number, since it uses less digits than its factorization.

257565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 249.

The product of its digits is 10500, while the sum is 30.

The square root of 257565 is about 507.5086206164. The cubic root of 257565 is about 63.6251690265.

The spelling of 257565 in words is "two hundred fifty-seven thousand, five hundred sixty-five".