684691 has 4 divisors (see below), whose sum is σ = 782512. Its totient is φ = 586872.

The previous prime is 684683. The next prime is 684713. The reversal of 684691 is 196486.

684691 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 684691 - 2³ = 684683 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 (684091) 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, 48900 + ... + 48913.

It is an arithmetic number, because the mean of its divisors is an integer number (195628).

2⁶⁸⁴⁶⁹¹ is an apocalyptic number.

684691 is a deficient number, since it is larger than the sum of its proper divisors (97821).

684691 is an equidigital number, since it uses as much as digits as its factorization.

684691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97820.

The product of its digits is 10368, while the sum is 34.

The square root of 684691 is about 827.4605730789. The cubic root of 684691 is about 88.1383412895.

The spelling of 684691 in words is "six hundred eighty-four thousand, six hundred ninety-one".