257820 has 24 divisors (see below), whose sum is σ = 722064. Its totient is φ = 68736.

The previous prime is 257797. The next prime is 257837. The reversal of 257820 is 28752.

It is a congruent number.

It is an unprimeable number.

257820 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2089 + ... + 2208.

It is an arithmetic number, because the mean of its divisors is an integer number (30086).

2²⁵⁷⁸²⁰ is an apocalyptic number.

257820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

257820 is an abundant number, since it is smaller than the sum of its proper divisors (464244).

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

257820 is a wasteful number, since it uses less digits than its factorization.

257820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4309 (or 4307 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 24.

The square root of 257820 is about 507.7597857255. The cubic root of 257820 is about 63.6461592837.

The spelling of 257820 in words is "two hundred fifty-seven thousand, eight hundred twenty".