21211100121 has 4 divisors (see below), whose sum is σ = 28281466832. Its totient is φ = 14140733412.

The previous prime is 21211100117. The next prime is 21211100153. The reversal of 21211100121 is 12100111212.

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 not a de Polignac number, because 21211100121 - 2² = 21211100117 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21211100097 and 21211100106.

It is not an unprimeable number, because it can be changed into a prime (21211100111) 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 3 ways as a sum of consecutive naturals, for example, 3535183351 + ... + 3535183356.

It is an arithmetic number, because the mean of its divisors is an integer number (7070366708).

Almost surely, 2^21211100121 is an apocalyptic number.

It is an amenable number.

21211100121 is a deficient number, since it is larger than the sum of its proper divisors (7070366711).

21211100121 is an equidigital number, since it uses as much as digits as its factorization.

21211100121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7070366710.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21211100121 its reverse (12100111212), we get a palindrome (33311211333).

The spelling of 21211100121 in words is "twenty-one billion, two hundred eleven million, one hundred thousand, one hundred twenty-one".