7728739856640 has 720 divisors, whose sum is σ = 31480720419456. Its totient is φ = 1792165478400.

The previous prime is 7728739856639. The next prime is 7728739856671. The reversal of 7728739856640 is 466589378277.

7728739856640 is a `hidden beast` number, since 7 + 7 + 28 + 7 + 39 + 8 + 566 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (720).

It is a Harshad number since it is a multiple of its sum of digits (72).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 26083720 + ... + 26378360.

Almost surely, 2^{7728739856640} 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 7728739856640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15740360209728).

7728739856640 is an abundant number, since it is smaller than the sum of its proper divisors (23751980562816).

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

7728739856640 is a wasteful number, since it uses less digits than its factorization.

7728739856640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 294708 (or 294685 counting only the distinct ones).

The product of its (nonzero) digits is 853493760, while the sum is 72.

The spelling of 7728739856640 in words is "seven trillion, seven hundred twenty-eight billion, seven hundred thirty-nine million, eight hundred fifty-six thousand, six hundred forty".