687997 has 4 divisors (see below), whose sum is σ = 690300. Its totient is φ = 685696.

The previous prime is 687977. The next prime is 688003. The reversal of 687997 is 799786.

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

It can be written as a sum of positive squares in 2 ways, for example, as 423801 + 264196 = 651^2 + 514^2 .

It is a cyclic number.

It is not a de Polignac number, because 687997 - 2¹⁵ = 655229 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687917) 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, 622 + ... + 1327.

It is an arithmetic number, because the mean of its divisors is an integer number (172575).

2⁶⁸⁷⁹⁹⁷ is an apocalyptic number.

It is an amenable number.

687997 is a deficient number, since it is larger than the sum of its proper divisors (2303).

687997 is a wasteful number, since it uses less digits than its factorization.

687997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2302.

The product of its digits is 190512, while the sum is 46.

The square root of 687997 is about 829.4558457206. The cubic root of 687997 is about 88.2799709346.

The spelling of 687997 in words is "six hundred eighty-seven thousand, nine hundred ninety-seven".