21122011022221 has 2 divisors, whose sum is σ = 21122011022222. Its totient is φ = 21122011022220.

The previous prime is 21122011022207. The next prime is 21122011022243. The reversal of 21122011022221 is 12222011022112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18905634459721 + 2216376562500 = 4348061^2 + 1488750^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21122011022221 is a prime.

It is a super-2 number, since 2×21122011022221² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21122011022201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561005511110 + 10561005511111.

It is an arithmetic number, because the mean of its divisors is an integer number (10561005511111).

Almost surely, 2^{21122011022221} is an apocalyptic number.

It is an amenable number.

21122011022221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21122011022221 is an equidigital number, since it uses as much as digits as its factorization.

21122011022221 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 21122011022221 its reverse (12222011022112), we get a palindrome (33344022044333).

The spelling of 21122011022221 in words is "twenty-one trillion, one hundred twenty-two billion, eleven million, twenty-two thousand, two hundred twenty-one".