2001123121 has 16 divisors (see below), whose sum is σ = 2111776128. Its totient is φ = 1894032000.

The previous prime is 2001123109. The next prime is 2001123139. The reversal of 2001123121 is 1213211002.

It is a cyclic number.

It is not a de Polignac number, because 2001123121 - 2⁹ = 2001122609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2001123151) 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, 262455 + ... + 269971.

It is an arithmetic number, because the mean of its divisors is an integer number (131986008).

Almost surely, 2^2001123121 is an apocalyptic number.

It is an amenable number.

2001123121 is a deficient number, since it is larger than the sum of its proper divisors (110653007).

2001123121 is a wasteful number, since it uses less digits than its factorization.

2001123121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7752.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 2001123121 is about 44733.9146621442. The cubic root of 2001123121 is about 1260.1568463940.

Adding to 2001123121 its reverse (1213211002), we get a palindrome (3214334123).

The spelling of 2001123121 in words is "two billion, one million, one hundred twenty-three thousand, one hundred twenty-one".