161661166161 has 16 divisors (see below), whose sum is σ = 235885307328. Its totient is φ = 97667384000.

The previous prime is 161661166127. The next prime is 161661166169.

161661166161 is nontrivially palindromic in base 10.

It is a cyclic number.

It is not a de Polignac number, because 161661166161 - 2¹¹ = 161661164113 is a prime.

It is a super-2 number, since 2×161661166161² (a number of 23 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (161661166169) 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, 7716390 + ... + 7737311.

It is an arithmetic number, because the mean of its divisors is an integer number (14742831708).

Almost surely, 2^161661166161 is an apocalyptic number.

161661166161 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

161661166161 is a deficient number, since it is larger than the sum of its proper divisors (74224141167).

161661166161 is a wasteful number, since it uses less digits than its factorization.

161661166161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15454032.

The product of its digits is 46656, while the sum is 42.

The spelling of 161661166161 in words is "one hundred sixty-one billion, six hundred sixty-one million, one hundred sixty-six thousand, one hundred sixty-one".