21222001220221 has 4 divisors (see below), whose sum is σ = 22144696925472. Its totient is φ = 20299305514972.

The previous prime is 21222001220207. The next prime is 21222001220237. The reversal of 21222001220221 is 12202210022212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21222001220221 - 2²⁷ = 21221867002493 is a prime.

It is a super-2 number, since 2×21222001220221² (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 (21222001220261) 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, 461347852591 + ... + 461347852636.

It is an arithmetic number, because the mean of its divisors is an integer number (5536174231368).

Almost surely, 2^{21222001220221} is an apocalyptic number.

It is an amenable number.

21222001220221 is a deficient number, since it is larger than the sum of its proper divisors (922695705251).

21222001220221 is an equidigital number, since it uses as much as digits as its factorization.

21222001220221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 922695705250.

The product of its (nonzero) digits is 256, while the sum is 19.

Adding to 21222001220221 its reverse (12202210022212), we get a palindrome (33424211242433).

The spelling of 21222001220221 in words is "twenty-one trillion, two hundred twenty-two billion, one million, two hundred twenty thousand, two hundred twenty-one".