21220122121 has 16 divisors (see below), whose sum is σ = 23993625600. Its totient is φ = 18589916800.

The previous prime is 21220122107. The next prime is 21220122137. The reversal of 21220122121 is 12122102212.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21220122121 - 2²⁷ = 21085904393 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21220122095 and 21220122104.

It is not an unprimeable number, because it can be changed into a prime (21220122101) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 102360 + ... + 230038.

It is an arithmetic number, because the mean of its divisors is an integer number (1499601600).

Almost surely, 2^21220122121 is an apocalyptic number.

It is an amenable number.

21220122121 is a deficient number, since it is larger than the sum of its proper divisors (2773503479).

21220122121 is a wasteful number, since it uses less digits than its factorization.

21220122121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128240.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21220122121 its reverse (12122102212), we get a palindrome (33342224333).

It can be divided in two parts, 21220 and 122121, that added together give a palindrome (143341).

The spelling of 21220122121 in words is "twenty-one billion, two hundred twenty million, one hundred twenty-two thousand, one hundred twenty-one".