21222012021221 has 12 divisors (see below), whose sum is σ = 23533105132236. Its totient is φ = 19122005992320.

The previous prime is 21222012021191. The next prime is 21222012021227. The reversal of 21222012021221 is 12212021022212.

It can be written as a sum of positive squares in 2 ways, for example, as 10873598580196 + 10348413441025 = 3297514^2 + 3216895^2 .

It is not a de Polignac number, because 21222012021221 - 2⁶ = 21222012021157 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21222012021193 and 21222012021202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222012021227) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 776041766 + ... + 776069111.

It is an arithmetic number, because the mean of its divisors is an integer number (1961092094353).

Almost surely, 2^{21222012021221} is an apocalyptic number.

It is an amenable number.

21222012021221 is a deficient number, since it is larger than the sum of its proper divisors (2311093111015).

21222012021221 is a wasteful number, since it uses less digits than its factorization.

21222012021221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1552111012 (or 1552111001 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 20.

Adding to 21222012021221 its reverse (12212021022212), we get a palindrome (33434033043433).

Subtracting from 21222012021221 its reverse (12212021022212), we obtain a palindrome (9009990999009).

The spelling of 21222012021221 in words is "twenty-one trillion, two hundred twenty-two billion, twelve million, twenty-one thousand, two hundred twenty-one".