2001221011121 has 2 divisors, whose sum is σ = 2001221011122. Its totient is φ = 2001221011120.

The previous prime is 2001221011109. The next prime is 2001221011123. The reversal of 2001221011121 is 1211101221002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1197394005025 + 803827006096 = 1094255^2 + 896564^2 .

It is a cyclic number.

It is not a de Polignac number, because 2001221011121 - 2²² = 2001216816817 is a prime.

Together with 2001221011123, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 2001221011096 and 2001221011105.

It is not a weakly prime, because it can be changed into another prime (2001221011123) 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, 1000610505560 + 1000610505561.

It is an arithmetic number, because the mean of its divisors is an integer number (1000610505561).

Almost surely, 2^{2001221011121} is an apocalyptic number.

It is an amenable number.

2001221011121 is a deficient number, since it is larger than the sum of its proper divisors (1).

2001221011121 is an equidigital number, since it uses as much as digits as its factorization.

2001221011121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 2001221011121 its reverse (1211101221002), we get a palindrome (3212322232123).

The spelling of 2001221011121 in words is "two trillion, one billion, two hundred twenty-one million, eleven thousand, one hundred twenty-one".