2001221021121 has 24 divisors (see below), whose sum is σ = 3176119181664. Its totient is φ = 1116960566400.

The previous prime is 2001221021117. The next prime is 2001221021167. The reversal of 2001221021121 is 1211201221002.

It is not a de Polignac number, because 2001221021121 - 2² = 2001221021117 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2001221021121.

It is not an unprimeable number, because it can be changed into a prime (2001221022121) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 158293080 + ... + 158305721.

It is an arithmetic number, because the mean of its divisors is an integer number (132338299236).

Almost surely, 2^{2001221021121} is an apocalyptic number.

2001221021121 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2001221021121 is a deficient number, since it is larger than the sum of its proper divisors (1174898160543).

2001221021121 is a wasteful number, since it uses less digits than its factorization.

2001221021121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 316598861 (or 316598854 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 2001221021121 its reverse (1211201221002), we get a palindrome (3212422242123).

The spelling of 2001221021121 in words is "two trillion, one billion, two hundred twenty-one million, twenty-one thousand, one hundred twenty-one".