21122421011221 has 2 divisors, whose sum is σ = 21122421011222. Its totient is φ = 21122421011220.

The previous prime is 21122421011161. The next prime is 21122421011257. The reversal of 21122421011221 is 12211012422112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14942175291121 + 6180245720100 = 3865511^2 + 2486010^2 .

It is a cyclic number.

It is not a de Polignac number, because 21122421011221 - 2⁷ = 21122421011093 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21122421011192 and 21122421011201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21122421011281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561210505610 + 10561210505611.

It is an arithmetic number, because the mean of its divisors is an integer number (10561210505611).

Almost surely, 2^{21122421011221} is an apocalyptic number.

It is an amenable number.

21122421011221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21122421011221 is an equidigital number, since it uses as much as digits as its factorization.

21122421011221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 256, while the sum is 22.

Adding to 21122421011221 its reverse (12211012422112), we get a palindrome (33333433433333).

The spelling of 21122421011221 in words is "twenty-one trillion, one hundred twenty-two billion, four hundred twenty-one million, eleven thousand, two hundred twenty-one".