2181235181 has 2 divisors, whose sum is σ = 2181235182. Its totient is φ = 2181235180.

The previous prime is 2181235171. The next prime is 2181235187. The reversal of 2181235181 is 1815321812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1603602025 + 577633156 = 40045^2 + 24034^2 .

It is a cyclic number.

It is not a de Polignac number, because 2181235181 - 2⁶ = 2181235117 is a prime.

It is a super-2 number, since 2×2181235181² = 9515573829664205522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2181235187) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1090617590 + 1090617591.

It is an arithmetic number, because the mean of its divisors is an integer number (1090617591).

Almost surely, 2^2181235181 is an apocalyptic number.

It is an amenable number.

2181235181 is a deficient number, since it is larger than the sum of its proper divisors (1).

2181235181 is an equidigital number, since it uses as much as digits as its factorization.

2181235181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3840, while the sum is 32.

The square root of 2181235181 is about 46703.6955818274. The cubic root of 2181235181 is about 1296.8831010950.

Adding to 2181235181 its reverse (1815321812), we get a palindrome (3996556993).

The spelling of 2181235181 in words is "two billion, one hundred eighty-one million, two hundred thirty-five thousand, one hundred eighty-one".