212121221200181 has 2 divisors, whose sum is σ = 212121221200182. Its totient is φ = 212121221200180.

The previous prime is 212121221200157. The next prime is 212121221200249. The reversal of 212121221200181 is 181002122121212.

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., 202849774741156 + 9271446459025 = 14242534^2 + 3044905^2 .

It is a cyclic number.

It is not a de Polignac number, because 212121221200181 - 2²² = 212121217005877 is a prime.

It is a super-2 number, since 2×212121221200181² (a number of 29 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 212121221200181.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212121221200081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106060610600090 + 106060610600091.

It is an arithmetic number, because the mean of its divisors is an integer number (106060610600091).

Almost surely, 2^{212121221200181} is an apocalyptic number.

It is an amenable number.

212121221200181 is a deficient number, since it is larger than the sum of its proper divisors (1).

212121221200181 is an equidigital number, since it uses as much as digits as its factorization.

212121221200181 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 512, while the sum is 26.

Adding to 212121221200181 its reverse (181002122121212), we get a palindrome (393123343321393).

The spelling of 212121221200181 in words is "two hundred twelve trillion, one hundred twenty-one billion, two hundred twenty-one million, two hundred thousand, one hundred eighty-one".