6643868 has 72 divisors (see below), whose sum is σ = 15283296. Its totient is φ = 2471040.

The previous prime is 6643859. The next prime is 6643883. The reversal of 6643868 is 8683466.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 125330 + ... + 125382.

It is an arithmetic number, because the mean of its divisors is an integer number (212268).

Almost surely, 2^6643868 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 6643868, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7641648).

6643868 is an abundant number, since it is smaller than the sum of its proper divisors (8639428).

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

6643868 is a wasteful number, since it uses less digits than its factorization.

6643868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123 (or 110 counting only the distinct ones).

The product of its digits is 165888, while the sum is 41.

The square root of 6643868 is about 2577.5701736325. The cubic root of 6643868 is about 187.9924170776.

It can be divided in two parts, 66 and 43868, that added together give a palindrome (43934).

The spelling of 6643868 in words is "six million, six hundred forty-three thousand, eight hundred sixty-eight".