21221112020221 has 2 divisors, whose sum is σ = 21221112020222. Its totient is φ = 21221112020220.

The previous prime is 21221112020197. The next prime is 21221112020249. The reversal of 21221112020221 is 12202021112212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12211425415225 + 9009686604996 = 3494485^2 + 3001614^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221112020221 - 2¹¹ = 21221112018173 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21221112090221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610556010110 + 10610556010111.

It is an arithmetic number, because the mean of its divisors is an integer number (10610556010111).

Almost surely, 2^{21221112020221} is an apocalyptic number.

It is an amenable number.

21221112020221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221112020221 is an equidigital number, since it uses as much as digits as its factorization.

21221112020221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 21221112020221 its reverse (12202021112212), we get a palindrome (33423133132433).

The spelling of 21221112020221 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred twelve million, twenty thousand, two hundred twenty-one".