257421 has 8 divisors (see below), whose sum is σ = 349920. Its totient is φ = 168272.

The previous prime is 257407. The next prime is 257437. The reversal of 257421 is 124752.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 257421 - 2⁷ = 257293 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (257401) 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, 651 + ... + 968.

It is an arithmetic number, because the mean of its divisors is an integer number (43740).

2²⁵⁷⁴²¹ is an apocalyptic number.

It is an amenable number.

257421 is a deficient number, since it is larger than the sum of its proper divisors (92499).

257421 is a wasteful number, since it uses less digits than its factorization.

257421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1675.

The product of its digits is 560, while the sum is 21.

The square root of 257421 is about 507.3667312704. The cubic root of 257421 is about 63.6133095835.

The spelling of 257421 in words is "two hundred fifty-seven thousand, four hundred twenty-one".