2001001001221 has 2 divisors, whose sum is σ = 2001001001222. Its totient is φ = 2001001001220.

The previous prime is 2001001001191. The next prime is 2001001001227. The reversal of 2001001001221 is 1221001001002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1935746298721 + 65254702500 = 1391311^2 + 255450^2 .

It is a cyclic number.

It is not a de Polignac number, because 2001001001221 - 2¹⁹ = 2001000476933 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2001001001198 and 2001001001207.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2001001001227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1000500500610 + 1000500500611.

It is an arithmetic number, because the mean of its divisors is an integer number (1000500500611).

Almost surely, 2^{2001001001221} is an apocalyptic number.

It is an amenable number.

2001001001221 is a deficient number, since it is larger than the sum of its proper divisors (1).

2001001001221 is an equidigital number, since it uses as much as digits as its factorization.

2001001001221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 2001001001221 its reverse (1221001001002), we get a palindrome (3222002002223).

The spelling of 2001001001221 in words is "two trillion, one billion, one million, one thousand, two hundred twenty-one".