257986 has 4 divisors (see below), whose sum is σ = 386982. Its totient is φ = 128992.

The previous prime is 257981. The next prime is 257987. The reversal of 257986 is 689752.

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

It can be written as a sum of positive squares in only one way, i.e., 219961 + 38025 = 469^2 + 195^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (257981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64495 + ... + 64498.

2²⁵⁷⁹⁸⁶ is an apocalyptic number.

257986 is a deficient number, since it is larger than the sum of its proper divisors (128996).

257986 is a wasteful number, since it uses less digits than its factorization.

257986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128995.

The product of its digits is 30240, while the sum is 37.

The square root of 257986 is about 507.9232225445. The cubic root of 257986 is about 63.6598160930.

The spelling of 257986 in words is "two hundred fifty-seven thousand, nine hundred eighty-six".