12221221100021 has 6 divisors (see below), whose sum is σ = 12898297061622. Its totient is φ = 11577998936520.

The previous prime is 12221221100003. The next prime is 12221221100063. The reversal of 12221221100021 is 12000112212221.

It can be written as a sum of positive squares in only one way, i.e., 6935295915025 + 5285925184996 = 2633495^2 + 2299114^2 .

It is a de Polignac number, because none of the positive numbers 2^k-12221221100021 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 (12221221100521) 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, 16926898670 + ... + 16926899391.

It is an arithmetic number, because the mean of its divisors is an integer number (2149716176937).

Almost surely, 2^{12221221100021} is an apocalyptic number.

It is an amenable number.

12221221100021 is a deficient number, since it is larger than the sum of its proper divisors (677075961601).

12221221100021 is an equidigital number, since it uses as much as digits as its factorization.

12221221100021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33853798099 (or 33853798080 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 12221221100021 its reverse (12000112212221), we get a palindrome (24221333312242).

The spelling of 12221221100021 in words is "twelve trillion, two hundred twenty-one billion, two hundred twenty-one million, one hundred thousand, twenty-one".