21120002121 has 48 divisors (see below), whose sum is σ = 31071068160. Its totient is φ = 12743658720.

The previous prime is 21120002117. The next prime is 21120002179. The reversal of 21120002121 is 12120002112.

It is not a de Polignac number, because 21120002121 - 2² = 21120002117 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21120002097 and 21120002106.

It is not an unprimeable number, because it can be changed into a prime (21120002191) 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 in 47 ways as a sum of consecutive naturals, for example, 2648286 + ... + 2656248.

It is an arithmetic number, because the mean of its divisors is an integer number (647313920).

Almost surely, 2^21120002121 is an apocalyptic number.

It is an amenable number.

21120002121 is a deficient number, since it is larger than the sum of its proper divisors (9951066039).

21120002121 is a wasteful number, since it uses less digits than its factorization.

21120002121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8114 (or 8095 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21120002121 its reverse (12120002112), we get a palindrome (33240004233).

Subtracting from 21120002121 its reverse (12120002112), we obtain a palindrome (9000000009).

The spelling of 21120002121 in words is "twenty-one billion, one hundred twenty million, two thousand, one hundred twenty-one".