2164181 has 4 divisors (see below), whose sum is σ = 2167212. Its totient is φ = 2161152.

The previous prime is 2164177. The next prime is 2164193. The reversal of 2164181 is 1814612.

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 2 ways, for example, as 1540081 + 624100 = 1241^2 + 790^2 .

It is a cyclic number.

It is not a de Polignac number, because 2164181 - 2² = 2164177 is a prime.

It is a super-2 number, since 2×2164181² = 9367358801522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2164111) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 215 + ... + 2091.

It is an arithmetic number, because the mean of its divisors is an integer number (541803).

2^2164181 is an apocalyptic number.

It is an amenable number.

2164181 is a deficient number, since it is larger than the sum of its proper divisors (3031).

2164181 is a wasteful number, since it uses less digits than its factorization.

2164181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3030.

The product of its digits is 384, while the sum is 23.

The square root of 2164181 is about 1471.1155631017. The cubic root of 2164181 is about 129.3494321961.

Adding to 2164181 its reverse (1814612), we get a palindrome (3978793).

The spelling of 2164181 in words is "two million, one hundred sixty-four thousand, one hundred eighty-one".