7866115921 has 2 divisors, whose sum is σ = 7866115922. Its totient is φ = 7866115920.

The previous prime is 7866115903. The next prime is 7866115969. The reversal of 7866115921 is 1295116687.

7866115921 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., 7045923600 + 820192321 = 83940^2 + 28639^2 .

It is a cyclic number.

It is not a de Polignac number, because 7866115921 - 2⁵ = 7866115889 is a prime.

It is not a weakly prime, because it can be changed into another prime (7866115021) 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, 3933057960 + 3933057961.

It is an arithmetic number, because the mean of its divisors is an integer number (3933057961).

Almost surely, 2^7866115921 is an apocalyptic number.

It is an amenable number.

7866115921 is a deficient number, since it is larger than the sum of its proper divisors (1).

7866115921 is an equidigital number, since it uses as much as digits as its factorization.

7866115921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 181440, while the sum is 46.

The square root of 7866115921 is about 88691.1265065452. The cubic root of 7866115921 is about 1988.7801688111.

The spelling of 7866115921 in words is "seven billion, eight hundred sixty-six million, one hundred fifteen thousand, nine hundred twenty-one".