16691755920689 has 4 divisors (see below), whose sum is σ = 17142884459124. Its totient is φ = 16240627382256.

The previous prime is 16691755920611. The next prime is 16691755920733. The reversal of 16691755920689 is 98602955719661.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11236574410000 + 5455181510689 = 3352100^2 + 2335633^2 .

It is a cyclic number.

It is not a de Polignac number, because 16691755920689 - 2²⁴ = 16691739143473 is a prime.

It is a super-2 number, since 2×16691755920689² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16691755920089) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 225564269162 + ... + 225564269235.

It is an arithmetic number, because the mean of its divisors is an integer number (4285721114781).

Almost surely, 2^{16691755920689} is an apocalyptic number.

It is an amenable number.

16691755920689 is a deficient number, since it is larger than the sum of its proper divisors (451128538435).

16691755920689 is an equidigital number, since it uses as much as digits as its factorization.

16691755920689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 451128538434.

The product of its (nonzero) digits is 440899200, while the sum is 74.

The spelling of 16691755920689 in words is "sixteen trillion, six hundred ninety-one billion, seven hundred fifty-five million, nine hundred twenty thousand, six hundred eighty-nine".