257440 has 24 divisors (see below), whose sum is σ = 608580. Its totient is φ = 102912.

The previous prime is 257437. The next prime is 257443. The reversal of 257440 is 44752.

It is an interprime number because it is at equal distance from previous prime (257437) and next prime (257443).

It can be written as a sum of positive squares in 2 ways, for example, as 242064 + 15376 = 492^2 + 124^2 .

It is a nialpdrome in base 8.

It is not an unprimeable number, because it can be changed into a prime (257443) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 645 + ... + 964.

2²⁵⁷⁴⁴⁰ is an apocalyptic number.

257440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

257440 is an abundant number, since it is smaller than the sum of its proper divisors (351140).

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

257440 is a wasteful number, since it uses less digits than its factorization.

257440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1624 (or 1616 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 22.

The square root of 257440 is about 507.3854550537. The cubic root of 257440 is about 63.6148746243.

The spelling of 257440 in words is "two hundred fifty-seven thousand, four hundred forty".