6561722368 has 52 divisors (see below), whose sum is σ = 13280625288. Its totient is φ = 3241164800.

The previous prime is 6561722329. The next prime is 6561722389. The reversal of 6561722368 is 8632271656.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 330318 + ... + 349618.

Almost surely, 2^6561722368 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 6561722368, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (6640312644).

6561722368 is an abundant number, since it is smaller than the sum of its proper divisors (6718902920).

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

6561722368 is an equidigital number, since it uses as much as digits as its factorization.

6561722368 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19408 (or 19386 counting only the distinct ones).

The product of its digits is 725760, while the sum is 46.

The square root of 6561722368 is about 81004.4589389992. The cubic root of 6561722368 is about 1872.1441435748.

The spelling of 6561722368 in words is "six billion, five hundred sixty-one million, seven hundred twenty-two thousand, three hundred sixty-eight".