2001221022221 has 8 divisors (see below), whose sum is σ = 2002252942200. Its totient is φ = 2000189376000.

The previous prime is 2001221022211. The next prime is 2001221022277. The reversal of 2001221022221 is 1222201221002.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 365408160100 + 1635812862121 = 604490^2 + 1278989^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2001221022221 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 2001221022221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001221022211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15448721 + ... + 15577721.

It is an arithmetic number, because the mean of its divisors is an integer number (250281617775).

Almost surely, 2^{2001221022221} is an apocalyptic number.

It is an amenable number.

2001221022221 is a deficient number, since it is larger than the sum of its proper divisors (1031919979).

2001221022221 is a wasteful number, since it uses less digits than its factorization.

2001221022221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136879.

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

Adding to 2001221022221 its reverse (1222201221002), we get a palindrome (3223422243223).

The spelling of 2001221022221 in words is "two trillion, one billion, two hundred twenty-one million, twenty-two thousand, two hundred twenty-one".