687687 has 32 divisors (see below), whose sum is σ = 1236480. Its totient is φ = 328320.

The previous prime is 687683. The next prime is 687691. The reversal of 687687 is 786786.

It is an interprime number because it is at equal distance from previous prime (687683) and next prime (687691).

It is not a de Polignac number, because 687687 - 2² = 687683 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687683) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2889 + ... + 3117.

It is an arithmetic number, because the mean of its divisors is an integer number (38640).

2⁶⁸⁷⁶⁸⁷ is an apocalyptic number.

687687 is a deficient number, since it is larger than the sum of its proper divisors (548793).

687687 is a wasteful number, since it uses less digits than its factorization.

687687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 263.

The product of its digits is 112896, while the sum is 42.

The square root of 687687 is about 829.2689551647. The cubic root of 687687 is about 88.2667097806.

Subtracting 687687 from its reverse (786786), we obtain a palindrome (99099).

The spelling of 687687 in words is "six hundred eighty-seven thousand, six hundred eighty-seven".