687257 has 4 divisors (see below), whose sum is σ = 691236. Its totient is φ = 683280.

The previous prime is 687233. The next prime is 687277. The reversal of 687257 is 752786.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 752786 = 2 ⋅376393.

It can be written as a sum of positive squares in 2 ways, for example, as 8281 + 678976 = 91^2 + 824^2 .

It is a cyclic number.

It is not a de Polignac number, because 687257 - 2¹⁶ = 621721 is a prime.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 687257.

It is not an unprimeable number, because it can be changed into a prime (687277) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1718 + ... + 2079.

It is an arithmetic number, because the mean of its divisors is an integer number (172809).

2⁶⁸⁷²⁵⁷ is an apocalyptic number.

It is an amenable number.

687257 is a deficient number, since it is larger than the sum of its proper divisors (3979).

687257 is a wasteful number, since it uses less digits than its factorization.

687257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3978.

The product of its digits is 23520, while the sum is 35.

The square root of 687257 is about 829.0096501248. The cubic root of 687257 is about 88.2483086772.

The spelling of 687257 in words is "six hundred eighty-seven thousand, two hundred fifty-seven".