684609 has 4 divisors (see below), whose sum is σ = 912816. Its totient is φ = 456404.

The previous prime is 684599. The next prime is 684617. The reversal of 684609 is 906486.

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.

It is a cyclic number.

It is not a de Polignac number, because 684609 - 2¹⁵ = 651841 is a prime.

It is a D-number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 684609.

It is not an unprimeable number, because it can be changed into a prime (684109) 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, 114099 + ... + 114104.

It is an arithmetic number, because the mean of its divisors is an integer number (228204).

2⁶⁸⁴⁶⁰⁹ is an apocalyptic number.

It is an amenable number.

684609 is a deficient number, since it is larger than the sum of its proper divisors (228207).

684609 is a wasteful number, since it uses less digits than its factorization.

684609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 228206.

The product of its (nonzero) digits is 10368, while the sum is 33.

The square root of 684609 is about 827.4110224066. The cubic root of 684609 is about 88.1348226061.

The spelling of 684609 in words is "six hundred eighty-four thousand, six hundred nine".