2001222221121 has 16 divisors (see below), whose sum is σ = 2964797792320. Its totient is φ = 1334137288320.

The previous prime is 2001222221087. The next prime is 2001222221161. The reversal of 2001222221121 is 1211222221002.

It is a happy number.

2001222221121 is a `hidden beast` number, since 200 + 1 + 222 + 221 + 1 + 21 = 666.

It is not a de Polignac number, because 2001222221121 - 2⁹ = 2001222220609 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2001222221094 and 2001222221103.

It is not an unprimeable number, because it can be changed into a prime (2001222221161) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4421841 + ... + 4853361.

It is an arithmetic number, because the mean of its divisors is an integer number (185299862020).

Almost surely, 2^{2001222221121} is an apocalyptic number.

It is an amenable number.

2001222221121 is a deficient number, since it is larger than the sum of its proper divisors (963575571199).

2001222221121 is a wasteful number, since it uses less digits than its factorization.

2001222221121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 603293 (or 603287 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 2001222221121 its reverse (1211222221002), we get a palindrome (3212444442123).

The spelling of 2001222221121 in words is "two trillion, one billion, two hundred twenty-two million, two hundred twenty-one thousand, one hundred twenty-one".