21211330121 has 4 divisors (see below), whose sum is σ = 21704616912. Its totient is φ = 20718043332.

The previous prime is 21211330087. The next prime is 21211330177. The reversal of 21211330121 is 12103311212.

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 not a de Polignac number, because 21211330121 - 2⁶ = 21211330057 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21211330121.

It is not an unprimeable number, because it can be changed into a prime (21211330421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 246643331 + ... + 246643416.

It is an arithmetic number, because the mean of its divisors is an integer number (5426154228).

Almost surely, 2^21211330121 is an apocalyptic number.

It is an amenable number.

21211330121 is a deficient number, since it is larger than the sum of its proper divisors (493286791).

21211330121 is an equidigital number, since it uses as much as digits as its factorization.

21211330121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 493286790.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21211330121 its reverse (12103311212), we get a palindrome (33314641333).

The spelling of 21211330121 in words is "twenty-one billion, two hundred eleven million, three hundred thirty thousand, one hundred twenty-one".