6688904 has 16 divisors (see below), whose sum is σ = 12848220. Its totient is φ = 3262720.

The previous prime is 6688859. The next prime is 6688907. The reversal of 6688904 is 4098866.

It can be written as a sum of positive squares in 2 ways, for example, as 6240004 + 448900 = 2498^2 + 670^2 .

It is a Harshad number since it is a multiple of its sum of digits (41).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6688907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9869 + ... + 10524.

Almost surely, 2^6688904 is an apocalyptic number.

It is an amenable number.

6688904 is a deficient number, since it is larger than the sum of its proper divisors (6159316).

6688904 is a wasteful number, since it uses less digits than its factorization.

6688904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20440 (or 20436 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 41.

The square root of 6688904 is about 2586.2915535569. The cubic root of 6688904 is about 188.4162348543.

The spelling of 6688904 in words is "six million, six hundred eighty-eight thousand, nine hundred four".