2001221222101 has 4 divisors (see below), whose sum is σ = 2023706853900. Its totient is φ = 1978735590304.

The previous prime is 2001221222071. The next prime is 2001221222107. The reversal of 2001221222101 is 1012221221002.

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 1362708357201 + 638512864900 = 1167351^2 + 799070^2 .

It is a cyclic number.

It is not a de Polignac number, because 2001221222101 - 2⁷ = 2001221221973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2001221222107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11242815766 + ... + 11242815943.

It is an arithmetic number, because the mean of its divisors is an integer number (505926713475).

Almost surely, 2^{2001221222101} is an apocalyptic number.

It is an amenable number.

2001221222101 is a deficient number, since it is larger than the sum of its proper divisors (22485631799).

2001221222101 is an equidigital number, since it uses as much as digits as its factorization.

2001221222101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22485631798.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 2001221222101 its reverse (1012221221002), we get a palindrome (3013442443103).

The spelling of 2001221222101 in words is "two trillion, one billion, two hundred twenty-one million, two hundred twenty-two thousand, one hundred one".