257531 has 4 divisors (see below), whose sum is σ = 268752. Its totient is φ = 246312.

The previous prime is 257519. The next prime is 257539. The reversal of 257531 is 135752.

257531 = T₁₃₈ + T₁₃₉ + ... + T₁₆₀.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-257531 is a prime.

It is a super-2 number, since 2×257531² = 132644431922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 11197 = 257531 / (2 + 5 + 7 + 5 + 3 + 1).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 257497 and 257506.

It is not an unprimeable number, because it can be changed into a prime (257539) 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, 5576 + ... + 5621.

It is an arithmetic number, because the mean of its divisors is an integer number (67188).

2²⁵⁷⁵³¹ is an apocalyptic number.

257531 is a deficient number, since it is larger than the sum of its proper divisors (11221).

257531 is a wasteful number, since it uses less digits than its factorization.

257531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11220.

The product of its digits is 1050, while the sum is 23.

The square root of 257531 is about 507.4751225430. The cubic root of 257531 is about 63.6223692789.

The spelling of 257531 in words is "two hundred fifty-seven thousand, five hundred thirty-one".