684559 has 2 divisors, whose sum is σ = 684560. Its totient is φ = 684558.

The previous prime is 684557. The next prime is 684569. The reversal of 684559 is 955486.

684559 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 684559 - 2¹ = 684557 is a prime.

Together with 684557, it forms a pair of twin primes.

684559 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (684557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342279 + 342280.

It is an arithmetic number, because the mean of its divisors is an integer number (342280).

2⁶⁸⁴⁵⁵⁹ is an apocalyptic number.

684559 is a deficient number, since it is larger than the sum of its proper divisors (1).

684559 is an equidigital number, since it uses as much as digits as its factorization.

684559 is an evil number, because the sum of its binary digits is even.

The product of its digits is 43200, while the sum is 37.

The square root of 684559 is about 827.3808071257. The cubic root of 684559 is about 88.1326769296.

The spelling of 684559 in words is "six hundred eighty-four thousand, five hundred fifty-nine".