2001121311221 has 4 divisors (see below), whose sum is σ = 2001595627200. Its totient is φ = 2000646995244.

The previous prime is 2001121311199. The next prime is 2001121311229. The reversal of 2001121311221 is 1221131211002.

It is a happy number.

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 2001121311221 - 2³⁴ = 1983941442037 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2001121311221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001121311229) 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, 237151661 + ... + 237160098.

It is an arithmetic number, because the mean of its divisors is an integer number (500398906800).

Almost surely, 2^{2001121311221} is an apocalyptic number.

It is an amenable number.

2001121311221 is a deficient number, since it is larger than the sum of its proper divisors (474315979).

2001121311221 is an equidigital number, since it uses as much as digits as its factorization.

2001121311221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 474315978.

The product of its (nonzero) digits is 48, while the sum is 17.

Adding to 2001121311221 its reverse (1221131211002), we get a palindrome (3222252522223).

The spelling of 2001121311221 in words is "two trillion, one billion, one hundred twenty-one million, three hundred eleven thousand, two hundred twenty-one".