2001222221161 has 2 divisors, whose sum is σ = 2001222221162. Its totient is φ = 2001222221160.

The previous prime is 2001222221087. The next prime is 2001222221209. The reversal of 2001222221161 is 1611222221002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1414398811225 + 586823409936 = 1189285^2 + 766044^2 .

It is a cyclic number.

It is not a de Polignac number, because 2001222221161 - 2²¹ = 2001220124009 is a prime.

It is not a weakly prime, because it can be changed into another prime (2001222222161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1000611110580 + 1000611110581.

It is an arithmetic number, because the mean of its divisors is an integer number (1000611110581).

Almost surely, 2^{2001222221161} is an apocalyptic number.

It is an amenable number.

2001222221161 is a deficient number, since it is larger than the sum of its proper divisors (1).

2001222221161 is an equidigital number, since it uses as much as digits as its factorization.

2001222221161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 384, while the sum is 22.

Adding to 2001222221161 its reverse (1611222221002), we get a palindrome (3612444442163).

The spelling of 2001222221161 in words is "two trillion, one billion, two hundred twenty-two million, two hundred twenty-one thousand, one hundred sixty-one".