17664420874721 has 2 divisors, whose sum is σ = 17664420874722. Its totient is φ = 17664420874720.

The previous prime is 17664420874699. The next prime is 17664420874741. The reversal of 17664420874721 is 12747802446671.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13758639421696 + 3905781453025 = 3709264^2 + 1976305^2 .

It is an emirp because it is prime and its reverse (12747802446671) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 17664420874721 - 2⁴² = 13266374363617 is a prime.

It is not a weakly prime, because it can be changed into another prime (17664420874741) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8832210437360 + 8832210437361.

It is an arithmetic number, because the mean of its divisors is an integer number (8832210437361).

Almost surely, 2^{17664420874721} is an apocalyptic number.

It is an amenable number.

17664420874721 is a deficient number, since it is larger than the sum of its proper divisors (1).

17664420874721 is an equidigital number, since it uses as much as digits as its factorization.

17664420874721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25288704, while the sum is 59.

The spelling of 17664420874721 in words is "seventeen trillion, six hundred sixty-four billion, four hundred twenty million, eight hundred seventy-four thousand, seven hundred twenty-one".