21211222202221 has 8 divisors (see below), whose sum is σ = 22477830089400. Its totient is φ = 19980293410560.

The previous prime is 21211222202197. The next prime is 21211222202227. The reversal of 21211222202221 is 12220222211212.

It can be written as a sum of positive squares in 4 ways, for example, as 2480590350121 + 18730631852100 = 1574989^2 + 4327890^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21211222202221 - 2¹¹ = 21211222200173 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21211222202192 and 21211222202201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211222202227) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8919772656 + ... + 8919775033.

It is an arithmetic number, because the mean of its divisors is an integer number (2809728761175).

Almost surely, 2^{21211222202221} is an apocalyptic number.

It is an amenable number.

21211222202221 is a deficient number, since it is larger than the sum of its proper divisors (1266607887179).

21211222202221 is a wasteful number, since it uses less digits than its factorization.

21211222202221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17839547759.

The product of its (nonzero) digits is 512, while the sum is 22.

Adding to 21211222202221 its reverse (12220222211212), we get a palindrome (33431444413433).

The spelling of 21211222202221 in words is "twenty-one trillion, two hundred eleven billion, two hundred twenty-two million, two hundred two thousand, two hundred twenty-one".