21120202121 has 8 divisors (see below), whose sum is σ = 21643826400. Its totient is φ = 20596982560.

The previous prime is 21120202097. The next prime is 21120202139. The reversal of 21120202121 is 12120202112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21120202121 - 2⁶ = 21120202057 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21120202096 and 21120202105.

It is not an unprimeable number, because it can be changed into a prime (21120202421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5870 + ... + 205608.

It is an arithmetic number, because the mean of its divisors is an integer number (2705478300).

Almost surely, 2^21120202121 is an apocalyptic number.

It is an amenable number.

21120202121 is a deficient number, since it is larger than the sum of its proper divisors (523624279).

21120202121 is a wasteful number, since it uses less digits than its factorization.

21120202121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 202359.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21120202121 its reverse (12120202112), we get a palindrome (33240404233).

Subtracting from 21120202121 its reverse (12120202112), we obtain a palindrome (9000000009).

The spelling of 21120202121 in words is "twenty-one billion, one hundred twenty million, two hundred two thousand, one hundred twenty-one".