161643122811 has 6 divisors (see below), whose sum is σ = 233484510740. Its totient is φ = 107762081868.

The previous prime is 161643122759. The next prime is 161643122827. The reversal of 161643122811 is 118221346161.

161643122811 is a `hidden beast` number, since 1 + 6 + 1 + 64 + 312 + 281 + 1 = 666.

161643122811 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 161643122811 - 2¹¹ = 161643120763 is a prime.

It is a super-2 number, since 2×161643122811² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161643122411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8980173481 + ... + 8980173498.

Almost surely, 2^161643122811 is an apocalyptic number.

161643122811 is a deficient number, since it is larger than the sum of its proper divisors (71841387929).

161643122811 is a wasteful number, since it uses less digits than its factorization.

161643122811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17960346985 (or 17960346982 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

Adding to 161643122811 its reverse (118221346161), we get a palindrome (279864468972).

The spelling of 161643122811 in words is "one hundred sixty-one billion, six hundred forty-three million, one hundred twenty-two thousand, eight hundred eleven".