16668350221 has 2 divisors, whose sum is σ = 16668350222. Its totient is φ = 16668350220.

The previous prime is 16668350177. The next prime is 16668350243. The reversal of 16668350221 is 12205386661.

16668350221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13927304196 + 2741046025 = 118014^2 + 52355^2 .

It is a cyclic number.

It is not a de Polignac number, because 16668350221 - 2¹⁵ = 16668317453 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16668350291) 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, 8334175110 + 8334175111.

It is an arithmetic number, because the mean of its divisors is an integer number (8334175111).

Almost surely, 2^16668350221 is an apocalyptic number.

It is an amenable number.

16668350221 is a deficient number, since it is larger than the sum of its proper divisors (1).

16668350221 is an equidigital number, since it uses as much as digits as its factorization.

16668350221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 103680, while the sum is 40.

The spelling of 16668350221 in words is "sixteen billion, six hundred sixty-eight million, three hundred fifty thousand, two hundred twenty-one".