181891161169 has 3 divisors (see below), whose sum is σ = 181891587657. Its totient is φ = 181890734682.

The previous prime is 181891161167. The next prime is 181891161191. The reversal of 181891161169 is 961161198181.

It is a happy number.

The square root of 181891161169 is 426487.

It is a perfect power (a square), and thus also a powerful number.

181891161169 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, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 181891161169 - 2¹ = 181891161167 is a prime.

It is a super-2 number, since 2×181891161169² (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 (181891161161) 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 2 ways as a sum of consecutive naturals, for example, 213244 + ... + 639730.

It is an arithmetic number, because the mean of its divisors is an integer number (60630529219).

Almost surely, 2^181891161169 is an apocalyptic number.

181891161169 is the 426487-th square number.

181891161169 is the 213244-th centered octagonal number.

It is an amenable number.

181891161169 is a deficient number, since it is larger than the sum of its proper divisors (426488).

181891161169 is an frugal number, since it uses more digits than its factorization.

181891161169 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 852974 (or 426487 counting only the distinct ones).

The product of its digits is 186624, while the sum is 52.

The spelling of 181891161169 in words is "one hundred eighty-one billion, eight hundred ninety-one million, one hundred sixty-one thousand, one hundred sixty-nine".