22001221220021 has 4 divisors (see below), whose sum is σ = 22001232555372. Its totient is φ = 22001209884672.

The previous prime is 22001221219921. The next prime is 22001221220023. The reversal of 22001221220021 is 12002212210022.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 6819483079396 + 15181738140625 = 2611414^2 + 3896375^2 .

It is a cyclic number.

It is not a de Polignac number, because 22001221220021 - 2¹⁰ = 22001221218997 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 (22001221220023) 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, 1938266 + ... + 6910811.

It is an arithmetic number, because the mean of its divisors is an integer number (5500308138843).

Almost surely, 2^{22001221220021} is an apocalyptic number.

It is an amenable number.

22001221220021 is a deficient number, since it is larger than the sum of its proper divisors (11335351).

22001221220021 is an equidigital number, since it uses as much as digits as its factorization.

22001221220021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11335350.

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

Adding to 22001221220021 its reverse (12002212210022), we get a palindrome (34003433430043).

Subtracting from 22001221220021 its reverse (12002212210022), we obtain a palindrome (9999009009999).

The spelling of 22001221220021 in words is "twenty-two trillion, one billion, two hundred twenty-one million, two hundred twenty thousand, twenty-one".