21120001121 has 4 divisors (see below), whose sum is σ = 21120356544. Its totient is φ = 21119645700.

The previous prime is 21120001103. The next prime is 21120001127. The reversal of 21120001121 is 12110002112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21120001121 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21120001127) 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 3 ways as a sum of consecutive naturals, for example, 64565 + ... + 215426.

It is an arithmetic number, because the mean of its divisors is an integer number (5280089136).

Almost surely, 2^21120001121 is an apocalyptic number.

It is an amenable number.

21120001121 is a deficient number, since it is larger than the sum of its proper divisors (355423).

21120001121 is an equidigital number, since it uses as much as digits as its factorization.

21120001121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 355422.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21120001121 its reverse (12110002112), we get a palindrome (33230003233).

Subtracting from 21120001121 its reverse (12110002112), we obtain a palindrome (9009999009).

The spelling of 21120001121 in words is "twenty-one billion, one hundred twenty million, one thousand, one hundred twenty-one".