16661172557171 has 4 divisors (see below), whose sum is σ = 16726002022632. Its totient is φ = 16596343091712.

The previous prime is 16661172557137. The next prime is 16661172557261. The reversal of 16661172557171 is 17175527116661.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16661172557171 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16661172557971) 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, 32414732345 + ... + 32414732858.

It is an arithmetic number, because the mean of its divisors is an integer number (4181500505658).

Almost surely, 2^{16661172557171} is an apocalyptic number.

16661172557171 is a deficient number, since it is larger than the sum of its proper divisors (64829465461).

16661172557171 is an equidigital number, since it uses as much as digits as its factorization.

16661172557171 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64829465460.

The product of its digits is 3704400, while the sum is 56.

The spelling of 16661172557171 in words is "sixteen trillion, six hundred sixty-one billion, one hundred seventy-two million, five hundred fifty-seven thousand, one hundred seventy-one".