21112202205221 has 2 divisors, whose sum is σ = 21112202205222. Its totient is φ = 21112202205220.

The previous prime is 21112202205191. The next prime is 21112202205287. The reversal of 21112202205221 is 12250220221112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19683543784996 + 1428658420225 = 4436614^2 + 1195265^2 .

It is a cyclic number.

It is not a de Polignac number, because 21112202205221 - 2²⁶ = 21112135096357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21112402205221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10556101102610 + 10556101102611.

It is an arithmetic number, because the mean of its divisors is an integer number (10556101102611).

Almost surely, 2^{21112202205221} is an apocalyptic number.

It is an amenable number.

21112202205221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21112202205221 is an equidigital number, since it uses as much as digits as its factorization.

21112202205221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 640, while the sum is 23.

Adding to 21112202205221 its reverse (12250220221112), we get a palindrome (33362422426333).

The spelling of 21112202205221 in words is "twenty-one trillion, one hundred twelve billion, two hundred two million, two hundred five thousand, two hundred twenty-one".