7728754021 has 2 divisors, whose sum is σ = 7728754022. Its totient is φ = 7728754020.

The previous prime is 7728754001. The next prime is 7728754049. The reversal of 7728754021 is 1204578277.

7728754021 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4933517121 + 2795236900 = 70239^2 + 52870^2 .

It is a cyclic number.

It is not a de Polignac number, because 7728754021 - 2²⁹ = 7191883109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7728754001) by changing a digit.

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 as a sum of consecutive naturals, namely, 3864377010 + 3864377011.

It is an arithmetic number, because the mean of its divisors is an integer number (3864377011).

Almost surely, 2^7728754021 is an apocalyptic number.

It is an amenable number.

7728754021 is a deficient number, since it is larger than the sum of its proper divisors (1).

7728754021 is an equidigital number, since it uses as much as digits as its factorization.

7728754021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 219520, while the sum is 43.

The square root of 7728754021 is about 87913.3324416723. The cubic root of 7728754021 is about 1977.1357781623.

The spelling of 7728754021 in words is "seven billion, seven hundred twenty-eight million, seven hundred fifty-four thousand, twenty-one".