2001122220221 has 4 divisors (see below), whose sum is σ = 2002344654492. Its totient is φ = 1999899785952.

The previous prime is 2001122220203. The next prime is 2001122220257. The reversal of 2001122220221 is 1220222211002.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 650555164900 + 1350567055321 = 806570^2 + 1162139^2 .

It is a cyclic number.

It is not a de Polignac number, because 2001122220221 - 2²⁶ = 2001055111357 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 2001122220221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001122220121) 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, 611214680 + ... + 611217953.

It is an arithmetic number, because the mean of its divisors is an integer number (500586163623).

Almost surely, 2^{2001122220221} is an apocalyptic number.

It is an amenable number.

2001122220221 is a deficient number, since it is larger than the sum of its proper divisors (1222434271).

2001122220221 is a wasteful number, since it uses less digits than its factorization.

2001122220221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1222434270.

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 2001122220221 its reverse (1220222211002), we get a palindrome (3221344431223).

The spelling of 2001122220221 in words is "two trillion, one billion, one hundred twenty-two million, two hundred twenty thousand, two hundred twenty-one".