684409 has 4 divisors (see below), whose sum is σ = 746640. Its totient is φ = 622180.

The previous prime is 684407. The next prime is 684419. The reversal of 684409 is 904486.

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 684409 - 2¹ = 684407 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (684407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31099 + ... + 31120.

It is an arithmetic number, because the mean of its divisors is an integer number (186660).

2⁶⁸⁴⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

684409 is a deficient number, since it is larger than the sum of its proper divisors (62231).

684409 is a wasteful number, since it uses less digits than its factorization.

684409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62230.

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 684409 is about 827.2901546616. The cubic root of 684409 is about 88.1262392730.

The spelling of 684409 in words is "six hundred eighty-four thousand, four hundred nine".