12211210021 has 4 divisors (see below), whose sum is σ = 12221082892. Its totient is φ = 12201337152.

The previous prime is 12211210009. The next prime is 12211210043. The reversal of 12211210021 is 12001211221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12001211221 = 2861 ⋅4194761.

It can be written as a sum of positive squares in 2 ways, for example, as 4202928900 + 8008281121 = 64830^2 + 89489^2 .

It is a cyclic number.

It is not a de Polignac number, because 12211210021 - 2⁹ = 12211209509 is a prime.

It is a super-2 number, since 2×12211210021² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12211209983 and 12211210010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12211210321) 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, 4934580 + ... + 4937053.

It is an arithmetic number, because the mean of its divisors is an integer number (3055270723).

Almost surely, 2^12211210021 is an apocalyptic number.

It is an amenable number.

12211210021 is a deficient number, since it is larger than the sum of its proper divisors (9872871).

12211210021 is an equidigital number, since it uses as much as digits as its factorization.

12211210021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9872870.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 12211210021 its reverse (12001211221), we get a palindrome (24212421242).

The spelling of 12211210021 in words is "twelve billion, two hundred eleven million, two hundred ten thousand, twenty-one".