2001201122221 has 12 divisors (see below), whose sum is σ = 2408201211420. Its totient is φ = 1656166444800.

The previous prime is 2001201122213. The next prime is 2001201122233. The reversal of 2001201122221 is 1222211021002.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 570234909321 + 1430966212900 = 755139^2 + 1196230^2 .

It is not a de Polignac number, because 2001201122221 - 2³ = 2001201122213 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2001201122195 and 2001201122204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001201122201) 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 in 11 ways as a sum of consecutive naturals, for example, 704150980 + ... + 704153821.

It is an arithmetic number, because the mean of its divisors is an integer number (200683434285).

Almost surely, 2^{2001201122221} is an apocalyptic number.

It is an amenable number.

2001201122221 is a deficient number, since it is larger than the sum of its proper divisors (407000089199).

2001201122221 is a wasteful number, since it uses less digits than its factorization.

2001201122221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1408304844 (or 1408304837 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 2001201122221 its reverse (1222211021002), we get a palindrome (3223412143223).

The spelling of 2001201122221 in words is "two trillion, one billion, two hundred one million, one hundred twenty-two thousand, two hundred twenty-one".