211021221221081 has 2 divisors, whose sum is σ = 211021221221082. Its totient is φ = 211021221221080.

The previous prime is 211021221221077. The next prime is 211021221221101. The reversal of 211021221221081 is 180122122120112.

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., 113138216856025 + 97883004365056 = 10636645^2 + 9893584^2 .

It is a cyclic number.

It is not a de Polignac number, because 211021221221081 - 2² = 211021221221077 is a prime.

It is a super-2 number, since 2×211021221221081² (a number of 29 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 211021221221081.

It is not a weakly prime, because it can be changed into another prime (211021221221021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105510610610540 + 105510610610541.

It is an arithmetic number, because the mean of its divisors is an integer number (105510610610541).

Almost surely, 2^{211021221221081} is an apocalyptic number.

It is an amenable number.

211021221221081 is a deficient number, since it is larger than the sum of its proper divisors (1).

211021221221081 is an equidigital number, since it uses as much as digits as its factorization.

211021221221081 is an odious number, because the sum of its binary digits is odd.

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

Adding to 211021221221081 its reverse (180122122120112), we get a palindrome (391143343341193).

The spelling of 211021221221081 in words is "two hundred eleven trillion, twenty-one billion, two hundred twenty-one million, two hundred twenty-one thousand, eighty-one".