257720 has 32 divisors (see below), whose sum is σ = 615600. Its totient is φ = 96768.

The previous prime is 257717. The next prime is 257731. The reversal of 257720 is 27752.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 491 + ... + 869.

2²⁵⁷⁷²⁰ is an apocalyptic number.

257720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 257720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (307800).

257720 is an abundant number, since it is smaller than the sum of its proper divisors (357880).

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

257720 is a wasteful number, since it uses less digits than its factorization.

257720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 407 (or 403 counting only the distinct ones).

The product of its (nonzero) digits is 980, while the sum is 23.

The square root of 257720 is about 507.6613044147. The cubic root of 257720 is about 63.6379294605.

It can be divided in two parts, 2 and 57720, that multiplied together give a triangular number (115440 = T₄₈₀).

The spelling of 257720 in words is "two hundred fifty-seven thousand, seven hundred twenty".