684689 has 4 divisors (see below), whose sum is σ = 700656. Its totient is φ = 668724.

The previous prime is 684683. The next prime is 684713. The reversal of 684689 is 986486.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 986486 = 2 ⋅493243.

It is a cyclic number.

It is not a de Polignac number, because 684689 - 2⁸ = 684433 is a prime.

It is a d-powerful number, because it can be written as 6⁵ + 8³ + 6⁶ + 4⁸ + 8⁵ + 9⁶ .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (684683) 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, 7919 + ... + 8004.

It is an arithmetic number, because the mean of its divisors is an integer number (175164).

2⁶⁸⁴⁶⁸⁹ is an apocalyptic number.

It is an amenable number.

684689 is a deficient number, since it is larger than the sum of its proper divisors (15967).

684689 is a wasteful number, since it uses less digits than its factorization.

684689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15966.

The product of its digits is 82944, while the sum is 41.

The square root of 684689 is about 827.4593645612. The cubic root of 684689 is about 88.1382554713.

The spelling of 684689 in words is "six hundred eighty-four thousand, six hundred eighty-nine".