6440777728 has 288 divisors, whose sum is σ = 16731187200. Its totient is φ = 2424913920.

The previous prime is 6440777723. The next prime is 6440777741. The reversal of 6440777728 is 8277770446.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6440777723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 81528793 + ... + 81528871.

It is an arithmetic number, because the mean of its divisors is an integer number (58094400).

Almost surely, 2^6440777728 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 6440777728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8365593600).

6440777728 is an abundant number, since it is smaller than the sum of its proper divisors (10290409472).

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

6440777728 is a wasteful number, since it uses less digits than its factorization.

6440777728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 177 (or 146 counting only the distinct ones).

The product of its (nonzero) digits is 3687936, while the sum is 52.

The square root of 6440777728 is about 80254.4561255012. The cubic root of 6440777728 is about 1860.5703850563.

The spelling of 6440777728 in words is "six billion, four hundred forty million, seven hundred seventy-seven thousand, seven hundred twenty-eight".