2181081165 has 16 divisors (see below), whose sum is σ = 3499459200. Its totient is φ = 1160000192.

The previous prime is 2181081151. The next prime is 2181081211. The reversal of 2181081165 is 5611801812.

It is a cyclic number.

It is not a de Polignac number, because 2181081165 - 2⁷ = 2181081037 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 197130 + ... + 207899.

It is an arithmetic number, because the mean of its divisors is an integer number (218716200).

Almost surely, 2^2181081165 is an apocalyptic number.

It is an amenable number.

2181081165 is a deficient number, since it is larger than the sum of its proper divisors (1318378035).

2181081165 is a wasteful number, since it uses less digits than its factorization.

2181081165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 405396.

The product of its (nonzero) digits is 3840, while the sum is 33.

The square root of 2181081165 is about 46702.0466896259. The cubic root of 2181081165 is about 1296.8525762727.

Adding to 2181081165 its reverse (5611801812), we get a palindrome (7792882977).

The spelling of 2181081165 in words is "two billion, one hundred eighty-one million, eighty-one thousand, one hundred sixty-five".