21122200121221 has 4 divisors (see below), whose sum is σ = 21123177253452. Its totient is φ = 21121222988992.

The previous prime is 21122200121203. The next prime is 21122200121263. The reversal of 21122200121221 is 12212100222112.

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 3878985396196 + 17243214725025 = 1969514^2 + 4152495^2 .

It is a cyclic number.

It is not a de Polignac number, because 21122200121221 - 2⁵ = 21122200121189 is a prime.

It is a super-2 number, since 2×21122200121221² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21122200121021) 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, 488533690 + ... + 488576923.

It is an arithmetic number, because the mean of its divisors is an integer number (5280794313363).

Almost surely, 2^{21122200121221} is an apocalyptic number.

It is an amenable number.

21122200121221 is a deficient number, since it is larger than the sum of its proper divisors (977132231).

21122200121221 is an equidigital number, since it uses as much as digits as its factorization.

21122200121221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 977132230.

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 21122200121221 its reverse (12212100222112), we get a palindrome (33334300343333).

The spelling of 21122200121221 in words is "twenty-one trillion, one hundred twenty-two billion, two hundred million, one hundred twenty-one thousand, two hundred twenty-one".