21212011121 has 4 divisors (see below), whose sum is σ = 24242298432. Its totient is φ = 18181723812.

The previous prime is 21212011109. The next prime is 21212011147. The reversal of 21212011121 is 12111021212.

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 21212011121 - 2⁶ = 21212011057 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21212011096 and 21212011105.

It is not an unprimeable number, because it can be changed into a prime (21212011151) 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, 1515143645 + ... + 1515143658.

It is an arithmetic number, because the mean of its divisors is an integer number (6060574608).

Almost surely, 2^21212011121 is an apocalyptic number.

It is an amenable number.

21212011121 is a deficient number, since it is larger than the sum of its proper divisors (3030287311).

21212011121 is an equidigital number, since it uses as much as digits as its factorization.

21212011121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3030287310.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21212011121 its reverse (12111021212), we get a palindrome (33323032333).

The spelling of 21212011121 in words is "twenty-one billion, two hundred twelve million, eleven thousand, one hundred twenty-one".