684385 has 8 divisors (see below), whose sum is σ = 884520. Its totient is φ = 505344.

The previous prime is 684379. The next prime is 684407. The reversal of 684385 is 583486.

It can be written as a sum of positive squares in 4 ways, for example, as 57121 + 627264 = 239^2 + 792^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 684385 - 2⁹ = 683873 is a prime.

684385 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 684385.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5200 + ... + 5329.

It is an arithmetic number, because the mean of its divisors is an integer number (110565).

2⁶⁸⁴³⁸⁵ is an apocalyptic number.

684385 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

684385 is a deficient number, since it is larger than the sum of its proper divisors (200135).

684385 is a wasteful number, since it uses less digits than its factorization.

684385 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10547.

The product of its digits is 23040, while the sum is 34.

The square root of 684385 is about 827.2756493455. The cubic root of 684385 is about 88.1252091607.

The spelling of 684385 in words is "six hundred eighty-four thousand, three hundred eighty-five".