2001022221204 has 18 divisors (see below), whose sum is σ = 5058139503690. Its totient is φ = 667007407056.

The previous prime is 2001022221203. The next prime is 2001022221217. The reversal of 2001022221204 is 4021222201002.

It can be written as a sum of positive squares in only one way, i.e., 1480529232900 + 520492988304 = 1216770^2 + 721452^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001022221203) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 27791975259 + ... + 27791975330.

It is an arithmetic number, because the mean of its divisors is an integer number (281007750205).

Almost surely, 2^{2001022221204} is an apocalyptic number.

It is an amenable number.

2001022221204 is an abundant number, since it is smaller than the sum of its proper divisors (3057117282486).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2001022221204 is a wasteful number, since it uses less digits than its factorization.

2001022221204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55583950599 (or 55583950594 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

Adding to 2001022221204 its reverse (4021222201002), we get a palindrome (6022244422206).

The spelling of 2001022221204 in words is "two trillion, one billion, twenty-two million, two hundred twenty-one thousand, two hundred four".