2001022221221 has 8 divisors (see below), whose sum is σ = 2070051079800. Its totient is φ = 1931995235520.

The previous prime is 2001022221217. The next prime is 2001022221227. The reversal of 2001022221221 is 1221222201002.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 577501204225 + 1423521016996 = 759935^2 + 1193114^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 2001022221221 - 2² = 2001022221217 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 2001022221221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001022221227) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1910351 + ... + 2766131.

It is an arithmetic number, because the mean of its divisors is an integer number (258756384975).

Almost surely, 2^{2001022221221} is an apocalyptic number.

It is an amenable number.

2001022221221 is a deficient number, since it is larger than the sum of its proper divisors (69028858579).

2001022221221 is an equidigital number, since it uses as much as digits as its factorization.

2001022221221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 936439.

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

Adding to 2001022221221 its reverse (1221222201002), we get a palindrome (3222244422223).

The spelling of 2001022221221 in words is "two trillion, one billion, twenty-two million, two hundred twenty-one thousand, two hundred twenty-one".