6816944640 has 640 divisors, whose sum is σ = 26021191680. Its totient is φ = 1504051200.

The previous prime is 6816944579. The next prime is 6816944647. The reversal of 6816944640 is 464496186.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (640).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 6816944640.

It is not an unprimeable number, because it can be changed into a prime (6816944647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 49758652 + ... + 49758788.

It is an arithmetic number, because the mean of its divisors is an integer number (40658112).

Almost surely, 2^6816944640 is an apocalyptic number.

6816944640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6816944640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13010595840).

6816944640 is an abundant number, since it is smaller than the sum of its proper divisors (19204247040).

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

6816944640 is a wasteful number, since it uses less digits than its factorization.

6816944640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 224 (or 208 counting only the distinct ones).

The product of its (nonzero) digits is 995328, while the sum is 48.

The square root of 6816944640 is about 82564.7905586879. The cubic root of 6816944640 is about 1896.1088082262.

The spelling of 6816944640 in words is "six billion, eight hundred sixteen million, nine hundred forty-four thousand, six hundred forty".