16681784128349 has 2 divisors, whose sum is σ = 16681784128350. Its totient is φ = 16681784128348.

The previous prime is 16681784128301. The next prime is 16681784128363. The reversal of 16681784128349 is 94382148718661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14940157562500 + 1741626565849 = 3865250^2 + 1319707^2 .

It is a cyclic number.

It is not a de Polignac number, because 16681784128349 - 2⁴⁰ = 15582272500573 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16681784128549) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8340892064174 + 8340892064175.

It is an arithmetic number, because the mean of its divisors is an integer number (8340892064175).

Almost surely, 2^{16681784128349} is an apocalyptic number.

It is an amenable number.

16681784128349 is a deficient number, since it is larger than the sum of its proper divisors (1).

16681784128349 is an equidigital number, since it uses as much as digits as its factorization.

16681784128349 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 111476736, while the sum is 68.

The spelling of 16681784128349 in words is "sixteen trillion, six hundred eighty-one billion, seven hundred eighty-four million, one hundred twenty-eight thousand, three hundred forty-nine".