6661556116161 has 16 divisors (see below), whose sum is σ = 8888121105600. Its totient is φ = 4438014609600.

The previous prime is 6661556116129. The next prime is 6661556116177. The reversal of 6661556116161 is 1616116551666.

It is not a de Polignac number, because 6661556116161 - 2⁵ = 6661556116129 is a prime.

It is not an unprimeable number, because it can be changed into a prime (6661556116561) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 109084086 + ... + 109145136.

It is an arithmetic number, because the mean of its divisors is an integer number (555507569100).

Almost surely, 2^{6661556116161} is an apocalyptic number.

It is an amenable number.

6661556116161 is a deficient number, since it is larger than the sum of its proper divisors (2226564989439).

6661556116161 is a wasteful number, since it uses less digits than its factorization.

6661556116161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85216.

The product of its digits is 1166400, while the sum is 51.

The spelling of 6661556116161 in words is "six trillion, six hundred sixty-one billion, five hundred fifty-six million, one hundred sixteen thousand, one hundred sixty-one".