16661121112171 has 4 divisors (see below), whose sum is σ = 16667321755392. Its totient is φ = 16654920468952.

The previous prime is 16661121112147. The next prime is 16661121112187. The reversal of 16661121112171 is 17121112116661.

16661121112171 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 16661121112171 - 2¹⁵ = 16661121079403 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 16661121112171.

It is not an unprimeable number, because it can be changed into a prime (16661125112171) 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, 3100317580 + ... + 3100322953.

It is an arithmetic number, because the mean of its divisors is an integer number (4166830438848).

Almost surely, 2^{16661121112171} is an apocalyptic number.

16661121112171 is a deficient number, since it is larger than the sum of its proper divisors (6200643221).

16661121112171 is an equidigital number, since it uses as much as digits as its factorization.

16661121112171 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6200643220.

The product of its digits is 6048, while the sum is 37.

The spelling of 16661121112171 in words is "sixteen trillion, six hundred sixty-one billion, one hundred twenty-one million, one hundred twelve thousand, one hundred seventy-one".