6688040 has 32 divisors (see below), whose sum is σ = 15300360. Its totient is φ = 2630400.

The previous prime is 6688027. The next prime is 6688049. The reversal of 6688040 is 408866.

It can be written as a sum of positive squares in 4 ways, for example, as 2775556 + 3912484 = 1666^2 + 1978^2 .

It is a Smith number, since the sum of its digits (32) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 6687988 and 6688006.

It is not an unprimeable number, because it can be changed into a prime (6688049) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1070 + ... + 3810.

Almost surely, 2^6688040 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6688040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7650180).

6688040 is an abundant number, since it is smaller than the sum of its proper divisors (8612320).

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

6688040 is a wasteful number, since it uses less digits than its factorization.

6688040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2813 (or 2809 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 32.

The square root of 6688040 is about 2586.1245136304. The cubic root of 6688040 is about 188.4081219837.

The spelling of 6688040 in words is "six million, six hundred eighty-eight thousand, forty".