8664100721 has 2 divisors, whose sum is σ = 8664100722. Its totient is φ = 8664100720.

The previous prime is 8664100691. The next prime is 8664100777. The reversal of 8664100721 is 1270014668.

8664100721 is digitally balanced in base 2 and base 3, because in such bases 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., 7078866496 + 1585234225 = 84136^2 + 39815^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8664100721 is a prime.

It is not a weakly prime, because it can be changed into another prime (8664100021) 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 as a sum of consecutive naturals, namely, 4332050360 + 4332050361.

It is an arithmetic number, because the mean of its divisors is an integer number (4332050361).

Almost surely, 2^8664100721 is an apocalyptic number.

It is an amenable number.

8664100721 is a deficient number, since it is larger than the sum of its proper divisors (1).

8664100721 is an equidigital number, since it uses as much as digits as its factorization.

8664100721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16128, while the sum is 35.

The square root of 8664100721 is about 93081.1512659787. The cubic root of 8664100721 is about 2053.8773116324.

The spelling of 8664100721 in words is "eight billion, six hundred sixty-four million, one hundred thousand, seven hundred twenty-one".