2181142043161 has 3 divisors (see below), whose sum is σ = 2181143520031. Its totient is φ = 2181140566292.

The previous prime is 2181142043153. The next prime is 2181142043173. The reversal of 2181142043161 is 1613402411812.

The square root of 2181142043161 is 1476869.

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

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 can be written as a sum of positive squares in only one way, i.e., 2106361671561 + 74780371600 = 1451331^2 + 273460^2 .

It is not a de Polignac number, because 2181142043161 - 2³ = 2181142043153 is a prime.

It is a super-2 number, since 2×2181142043161² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2181142043131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 738435 + ... + 2215303.

Almost surely, 2^{2181142043161} is an apocalyptic number.

2181142043161 is the 1476869-th square number.

2181142043161 is the 738435-th centered octagonal number.

It is an amenable number.

2181142043161 is a deficient number, since it is larger than the sum of its proper divisors (1476870).

2181142043161 is an frugal number, since it uses more digits than its factorization.

2181142043161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2953738 (or 1476869 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 34.

Adding to 2181142043161 its reverse (1613402411812), we get a palindrome (3794544454973).

The spelling of 2181142043161 in words is "two trillion, one hundred eighty-one billion, one hundred forty-two million, forty-three thousand, one hundred sixty-one".