687680 has 56 divisors (see below), whose sum is σ = 1877568. Its totient is φ = 235008.

The previous prime is 687679. The next prime is 687683. The reversal of 687680 is 86786.

It is a tau number, because it is divible by the number of its divisors (56).

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a self number, because there is not a number n which added to its sum of digits gives 687680.

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 7 ways as a sum of consecutive naturals, for example, 2087 + ... + 2393.

It is an arithmetic number, because the mean of its divisors is an integer number (33528).

2⁶⁸⁷⁶⁸⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 687680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (938784).

687680 is an abundant number, since it is smaller than the sum of its proper divisors (1189888).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

687680 is a wasteful number, since it uses less digits than its factorization.

687680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 331 (or 321 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 35.

The square root of 687680 is about 829.2647345691. The cubic root of 687680 is about 88.2664102892.

The spelling of 687680 in words is "six hundred eighty-seven thousand, six hundred eighty".