16601033616221 has 2 divisors, whose sum is σ = 16601033616222. Its totient is φ = 16601033616220.

The previous prime is 16601033616217. The next prime is 16601033616227. The reversal of 16601033616221 is 12261633010661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15927969252196 + 673064364025 = 3990986^2 + 820405^2 .

It is a cyclic number.

It is not a de Polignac number, because 16601033616221 - 2² = 16601033616217 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16601033616227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8300516808110 + 8300516808111.

It is an arithmetic number, because the mean of its divisors is an integer number (8300516808111).

Almost surely, 2^{16601033616221} is an apocalyptic number.

It is an amenable number.

16601033616221 is a deficient number, since it is larger than the sum of its proper divisors (1).

16601033616221 is an equidigital number, since it uses as much as digits as its factorization.

16601033616221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 46656, while the sum is 38.

Adding to 16601033616221 its reverse (12261633010661), we get a palindrome (28862666626882).

The spelling of 16601033616221 in words is "sixteen trillion, six hundred one billion, thirty-three million, six hundred sixteen thousand, two hundred twenty-one".