684989 has 2 divisors, whose sum is σ = 684990. Its totient is φ = 684988.

The previous prime is 684977. The next prime is 685001. The reversal of 684989 is 989486.

It is a balanced prime because it is at equal distance from previous prime (684977) and next prime (685001).

It can be written as a sum of positive squares in only one way, i.e., 444889 + 240100 = 667^2 + 490^2 .

It is a cyclic number.

It is not a de Polignac number, because 684989 - 2⁴ = 684973 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (684949) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342494 + 342495.

It is an arithmetic number, because the mean of its divisors is an integer number (342495).

2⁶⁸⁴⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

684989 is a deficient number, since it is larger than the sum of its proper divisors (1).

684989 is an equidigital number, since it uses as much as digits as its factorization.

684989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 124416, while the sum is 44.

The square root of 684989 is about 827.6406224926. The cubic root of 684989 is about 88.1511263347.

The spelling of 684989 in words is "six hundred eighty-four thousand, nine hundred eighty-nine".