2001222212021 has 4 divisors (see below), whose sum is σ = 2001225524844. Its totient is φ = 2001218899200.

The previous prime is 2001222212009. The next prime is 2001222212053. The reversal of 2001222212021 is 1202122221002.

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 1853992684996 + 147229527025 = 1361614^2 + 383705^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2001222212021 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 (2001222292021) 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, 464300 + ... + 2053781.

It is an arithmetic number, because the mean of its divisors is an integer number (500306381211).

Almost surely, 2^{2001222212021} is an apocalyptic number.

It is an amenable number.

2001222212021 is a deficient number, since it is larger than the sum of its proper divisors (3312823).

2001222212021 is an equidigital number, since it uses as much as digits as its factorization.

2001222212021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3312822.

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

Adding to 2001222212021 its reverse (1202122221002), we get a palindrome (3203344433023).

The spelling of 2001222212021 in words is "two trillion, one billion, two hundred twenty-two million, two hundred twelve thousand, twenty-one".