6688321 has 4 divisors (see below), whose sum is σ = 6754644. Its totient is φ = 6622000.

The previous prime is 6688313. The next prime is 6688337. The reversal of 6688321 is 1238866.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5948721 + 739600 = 2439^2 + 860^2 .

It is a cyclic number.

It is not a de Polignac number, because 6688321 - 2³ = 6688313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6688301) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33010 + ... + 33211.

It is an arithmetic number, because the mean of its divisors is an integer number (1688661).

Almost surely, 2^6688321 is an apocalyptic number.

It is an amenable number.

6688321 is a deficient number, since it is larger than the sum of its proper divisors (66323).

6688321 is a wasteful number, since it uses less digits than its factorization.

6688321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66322.

The product of its digits is 13824, while the sum is 34.

The square root of 6688321 is about 2586.1788414570. The cubic root of 6688321 is about 188.4107606213.

The spelling of 6688321 in words is "six million, six hundred eighty-eight thousand, three hundred twenty-one".