687643 has 6 divisors (see below), whose sum is σ = 755972. Its totient is φ = 625020.

The previous prime is 687641. The next prime is 687647. The reversal of 687643 is 346786.

It is not a de Polignac number, because 687643 - 2¹ = 687641 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 687599 and 687608.

It is not an unprimeable number, because it can be changed into a prime (687641) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2721 + ... + 2962.

2⁶⁸⁷⁶⁴³ is an apocalyptic number.

687643 is a deficient number, since it is larger than the sum of its proper divisors (68329).

687643 is a wasteful number, since it uses less digits than its factorization.

687643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5705 (or 5694 counting only the distinct ones).

The product of its digits is 24192, while the sum is 34.

The square root of 687643 is about 829.2424253498. The cubic root of 687643 is about 88.2648272294.

The spelling of 687643 in words is "six hundred eighty-seven thousand, six hundred forty-three".