688109 has 6 divisors (see below), whose sum is σ = 731274. Its totient is φ = 647360.

The previous prime is 688097. The next prime is 688111. The reversal of 688109 is 901886.

It can be written as a sum of positive squares in 3 ways, for example, as 64009 + 624100 = 253^2 + 790^2 .

It is a de Polignac number, because none of the positive numbers 2^k-688109 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688139) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 902 + ... + 1479.

It is an arithmetic number, because the mean of its divisors is an integer number (121879).

2⁶⁸⁸¹⁰⁹ is an apocalyptic number.

It is an amenable number.

688109 is a deficient number, since it is larger than the sum of its proper divisors (43165).

688109 is a wasteful number, since it uses less digits than its factorization.

688109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2415 (or 2398 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 32.

The square root of 688109 is about 829.5233571154. The cubic root of 688109 is about 88.2847610815.

It can be divided in two parts, 688 and 109, that added together give a palindrome (797).

The spelling of 688109 in words is "six hundred eighty-eight thousand, one hundred nine".