16756665221 has 2 divisors, whose sum is σ = 16756665222. Its totient is φ = 16756665220.

The previous prime is 16756665209. The next prime is 16756665253. The reversal of 16756665221 is 12256665761.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14277621121 + 2479044100 = 119489^2 + 49790^2 .

It is an emirp because it is prime and its reverse (12256665761) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16756665221 - 2³⁰ = 15682923397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16756665521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8378332610 + 8378332611.

It is an arithmetic number, because the mean of its divisors is an integer number (8378332611).

Almost surely, 2^16756665221 is an apocalyptic number.

It is an amenable number.

16756665221 is a deficient number, since it is larger than the sum of its proper divisors (1).

16756665221 is an equidigital number, since it uses as much as digits as its factorization.

16756665221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 907200, while the sum is 47.

The spelling of 16756665221 in words is "sixteen billion, seven hundred fifty-six million, six hundred sixty-five thousand, two hundred twenty-one".