9664667021 has 2 divisors, whose sum is σ = 9664667022. Its totient is φ = 9664667020.

The previous prime is 9664666937. The next prime is 9664667087. The reversal of 9664667021 is 1207664669.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9484812100 + 179854921 = 97390^2 + 13411^2 .

It is an emirp because it is prime and its reverse (1207664669) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9664667021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9664666021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4832333510 + 4832333511.

It is an arithmetic number, because the mean of its divisors is an integer number (4832333511).

Almost surely, 2^9664667021 is an apocalyptic number.

It is an amenable number.

9664667021 is a deficient number, since it is larger than the sum of its proper divisors (1).

9664667021 is an equidigital number, since it uses as much as digits as its factorization.

9664667021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 653184, while the sum is 47.

The square root of 9664667021 is about 98309.0383484652. The cubic root of 9664667021 is about 2130.0786132608.

The spelling of 9664667021 in words is "nine billion, six hundred sixty-four million, six hundred sixty-seven thousand, twenty-one".