687665 has 8 divisors (see below), whose sum is σ = 900288. Its totient is φ = 500080.

The previous prime is 687647. The next prime is 687679. The reversal of 687665 is 566786.

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

It is not a de Polignac number, because 687665 - 2¹⁶ = 622129 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 6197 + ... + 6306.

It is an arithmetic number, because the mean of its divisors is an integer number (112536).

2⁶⁸⁷⁶⁶⁵ is an apocalyptic number.

It is an amenable number.

687665 is a deficient number, since it is larger than the sum of its proper divisors (212623).

687665 is a wasteful number, since it uses less digits than its factorization.

687665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12519.

The product of its digits is 60480, while the sum is 38.

The square root of 687665 is about 829.2556903634. The cubic root of 687665 is about 88.2657685150.

The spelling of 687665 in words is "six hundred eighty-seven thousand, six hundred sixty-five".