257521 has 8 divisors (see below), whose sum is σ = 288288. Its totient is φ = 228000.

The previous prime is 257519. The next prime is 257539. The reversal of 257521 is 125752.

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 257521 - 2¹ = 257519 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 257492 and 257501.

It is not an unprimeable number, because it can be changed into a prime (257501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 166 + ... + 736.

It is an arithmetic number, because the mean of its divisors is an integer number (36036).

2²⁵⁷⁵²¹ is an apocalyptic number.

It is an amenable number.

257521 is a deficient number, since it is larger than the sum of its proper divisors (30767).

257521 is a wasteful number, since it uses less digits than its factorization.

257521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 623.

The product of its digits is 700, while the sum is 22.

The square root of 257521 is about 507.4652697476. The cubic root of 257521 is about 63.6215457769.

Subtracting from 257521 its reverse (125752), we obtain a square (131769 = 363²).

The spelling of 257521 in words is "two hundred fifty-seven thousand, five hundred twenty-one".