2121212121181 has 2 divisors, whose sum is σ = 2121212121182. Its totient is φ = 2121212121180.

The previous prime is 2121212121151. The next prime is 2121212121233. The reversal of 2121212121181 is 1811212121212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1116105618681 + 1005106502500 = 1056459^2 + 1002550^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121212121181 - 2¹¹ = 2121212119133 is a prime.

It is a super-2 number, since 2×2121212121181² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2121212121151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1060606060590 + 1060606060591.

It is an arithmetic number, because the mean of its divisors is an integer number (1060606060591).

Almost surely, 2^{2121212121181} is an apocalyptic number.

It is an amenable number.

2121212121181 is a deficient number, since it is larger than the sum of its proper divisors (1).

2121212121181 is an equidigital number, since it uses as much as digits as its factorization.

2121212121181 is an evil number, because the sum of its binary digits is even.

The product of its digits is 256, while the sum is 25.

Adding to 2121212121181 its reverse (1811212121212), we get a palindrome (3932424242393).

The spelling of 2121212121181 in words is "two trillion, one hundred twenty-one billion, two hundred twelve million, one hundred twenty-one thousand, one hundred eighty-one".