21221221120211 has 16 divisors (see below), whose sum is σ = 24447574155264. Its totient is φ = 18043599921984.

The previous prime is 21221221120181. The next prime is 21221221120237. The reversal of 21221221120211 is 11202112212212.

It is not a de Polignac number, because 21221221120211 - 2¹⁴ = 21221221103827 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221221120111) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3910616 + ... + 7598378.

It is an arithmetic number, because the mean of its divisors is an integer number (1527973384704).

Almost surely, 2^{21221221120211} is an apocalyptic number.

21221221120211 is a deficient number, since it is larger than the sum of its proper divisors (3226353035053).

21221221120211 is a wasteful number, since it uses less digits than its factorization.

21221221120211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3694370.

The product of its (nonzero) digits is 128, while the sum is 20.

Adding to 21221221120211 its reverse (11202112212212), we get a palindrome (32423333332423).

The spelling of 21221221120211 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred twenty-one million, one hundred twenty thousand, two hundred eleven".