21220112202121 has 6 divisors (see below), whose sum is σ = 24684620316810. Its totient is φ = 18188667601776.

The previous prime is 21220112202077. The next prime is 21220112202287. The reversal of 21220112202121 is 12120221102212.

It can be written as a sum of positive squares in only one way, i.e., 19383450296896 + 1836661905225 = 4402664^2 + 1355235^2 .

It is not a de Polignac number, because 21220112202121 - 2¹⁷ = 21220112071049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21220112202721) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 216531757116 + ... + 216531757213.

It is an arithmetic number, because the mean of its divisors is an integer number (4114103386135).

Almost surely, 2^{21220112202121} is an apocalyptic number.

It is an amenable number.

21220112202121 is a deficient number, since it is larger than the sum of its proper divisors (3464508114689).

21220112202121 is an equidigital number, since it uses as much as digits as its factorization.

21220112202121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 433063514343 (or 433063514336 counting only the distinct ones).

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

Adding to 21220112202121 its reverse (12120221102212), we get a palindrome (33340333304333).

The spelling of 21220112202121 in words is "twenty-one trillion, two hundred twenty billion, one hundred twelve million, two hundred two thousand, one hundred twenty-one".