684788 has 18 divisors (see below), whose sum is σ = 1298934. Its totient is φ = 315744.

The previous prime is 684773. The next prime is 684791. The reversal of 684788 is 887486.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 88804 + 595984 = 298^2 + 772^2 .

It is an Ulam number.

It is a congruent number.

It is an unprimeable number.

684788 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 5 ways as a sum of consecutive naturals, for example, 170 + ... + 1182.

It is an arithmetic number, because the mean of its divisors is an integer number (72163).

2⁶⁸⁴⁷⁸⁸ is an apocalyptic number.

It is an amenable number.

684788 is a deficient number, since it is larger than the sum of its proper divisors (614146).

684788 is a wasteful number, since it uses less digits than its factorization.

684788 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1043 (or 1028 counting only the distinct ones).

The product of its digits is 86016, while the sum is 41.

The square root of 684788 is about 827.5191840677. The cubic root of 684788 is about 88.1425032718.

It can be divided in two parts, 68478 and 8, that added together give a palindrome (68486).

The spelling of 684788 in words is "six hundred eighty-four thousand, seven hundred eighty-eight".