684688638 has 8 divisors (see below), whose sum is σ = 1369377288. Its totient is φ = 228229544.

The previous prime is 684688597. The next prime is 684688639. The reversal of 684688638 is 836886486.

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

684688638 is an admirable number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (684688639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 57057381 + ... + 57057392.

It is an arithmetic number, because the mean of its divisors is an integer number (171172161).

Almost surely, 2^684688638 is an apocalyptic number.

684688638 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

684688638 is a wasteful number, since it uses less digits than its factorization.

684688638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114114778.

The product of its digits is 10616832, while the sum is 57.

The square root of 684688638 is about 26166.5557152637. Note that the first 3 decimals coincide. The cubic root of 684688638 is about 881.3823993819.

The spelling of 684688638 in words is "six hundred eighty-four million, six hundred eighty-eight thousand, six hundred thirty-eight".