684666 has 32 divisors (see below), whose sum is σ = 1574400. Its totient is φ = 220320.

The previous prime is 684647. The next prime is 684683. The reversal of 684666 is 666486.

684666 is nontrivially palindromic in base 16.

It is a self number, because there is not a number n which added to its sum of digits gives 684666.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 684666.

It is an unprimeable number.

684666 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 15 ways as a sum of consecutive naturals, for example, 1470 + ... + 1878.

It is an arithmetic number, because the mean of its divisors is an integer number (49200).

2⁶⁸⁴⁶⁶⁶ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 684666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (787200).

684666 is an abundant number, since it is smaller than the sum of its proper divisors (889734).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

684666 is a wasteful number, since it uses less digits than its factorization.

684666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 451 (or 445 counting only the distinct ones).

The product of its digits is 41472, while the sum is 36.

The square root of 684666 is about 827.4454664810. The cubic root of 684666 is about 88.1372685500.

The spelling of 684666 in words is "six hundred eighty-four thousand, six hundred sixty-six".