257656 has 32 divisors (see below), whose sum is σ = 570240. Its totient is φ = 106848.

The previous prime is 257639. The next prime is 257657. The reversal of 257656 is 656752.

It is a super-2 number, since 2×257656² = 132773228672, which contains 22 as substring.

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 polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2355 + ... + 2461.

It is an arithmetic number, because the mean of its divisors is an integer number (17820).

2²⁵⁷⁶⁵⁶ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 257656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (285120).

257656 is an abundant number, since it is smaller than the sum of its proper divisors (312584).

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

257656 is a wasteful number, since it uses less digits than its factorization.

257656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163 (or 159 counting only the distinct ones).

The product of its digits is 12600, while the sum is 31.

The square root of 257656 is about 507.5982663485. The cubic root of 257656 is about 63.6326612565.

The spelling of 257656 in words is "two hundred fifty-seven thousand, six hundred fifty-six".