21242312111221 has 2 divisors, whose sum is σ = 21242312111222. Its totient is φ = 21242312111220.

The previous prime is 21242312111179. The next prime is 21242312111257. The reversal of 21242312111221 is 12211121324212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19919386576996 + 1322925534225 = 4463114^2 + 1150185^2 .

It is a cyclic number.

It is not a de Polignac number, because 21242312111221 - 2¹³ = 21242312103029 is a prime.

It is a super-2 number, since 2×21242312111221² (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 (21242312111021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621156055610 + 10621156055611.

It is an arithmetic number, because the mean of its divisors is an integer number (10621156055611).

Almost surely, 2^{21242312111221} is an apocalyptic number.

It is an amenable number.

21242312111221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21242312111221 is an equidigital number, since it uses as much as digits as its factorization.

21242312111221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 768, while the sum is 25.

Adding to 21242312111221 its reverse (12211121324212), we get a palindrome (33453433435433).

The spelling of 21242312111221 in words is "twenty-one trillion, two hundred forty-two billion, three hundred twelve million, one hundred eleven thousand, two hundred twenty-one".