2001221211121 has 4 divisors (see below), whose sum is σ = 2183150412144. Its totient is φ = 1819292010100.

The previous prime is 2001221211113. The next prime is 2001221211131. The reversal of 2001221211121 is 1211121221002.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2001221211121 - 2³ = 2001221211113 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2001221211095 and 2001221211104.

It is not an unprimeable number, because it can be changed into a prime (2001221211131) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 90964600495 + ... + 90964600516.

It is an arithmetic number, because the mean of its divisors is an integer number (545787603036).

Almost surely, 2^{2001221211121} is an apocalyptic number.

It is an amenable number.

2001221211121 is a deficient number, since it is larger than the sum of its proper divisors (181929201023).

2001221211121 is a wasteful number, since it uses less digits than its factorization.

2001221211121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181929201022.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 2001221211121 its reverse (1211121221002), we get a palindrome (3212342432123).

The spelling of 2001221211121 in words is "two trillion, one billion, two hundred twenty-one million, two hundred eleven thousand, one hundred twenty-one".