687985 has 4 divisors (see below), whose sum is σ = 825588. Its totient is φ = 550384.

The previous prime is 687977. The next prime is 688003. The reversal of 687985 is 589786.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 589786 = 2 ⋅294893.

It can be written as a sum of positive squares in 2 ways, for example, as 287296 + 400689 = 536^2 + 633^2 .

It is a cyclic number.

It is not a de Polignac number, because 687985 - 2³ = 687977 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 (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68794 + ... + 68803.

It is an arithmetic number, because the mean of its divisors is an integer number (206397).

2⁶⁸⁷⁹⁸⁵ is an apocalyptic number.

It is an amenable number.

687985 is a deficient number, since it is larger than the sum of its proper divisors (137603).

687985 is a wasteful number, since it uses less digits than its factorization.

687985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137602.

The product of its digits is 120960, while the sum is 43.

The square root of 687985 is about 829.4486120309. The cubic root of 687985 is about 88.2794576737.

The spelling of 687985 in words is "six hundred eighty-seven thousand, nine hundred eighty-five".