12121102212221 has 4 divisors (see below), whose sum is σ = 12134038288092. Its totient is φ = 12108166136352.

The previous prime is 12121102212199. The next prime is 12121102212251. The reversal of 12121102212221 is 12221220112121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1871410320025 + 10249691892196 = 1367995^2 + 3201514^2 .

It is a cyclic number.

It is not a de Polignac number, because 12121102212221 - 2¹⁴ = 12121102195837 is a prime.

It is a super-2 number, since 2×12121102212221² (a number of 27 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 = 12121102212193 and 12121102212202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12121102212251) 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, 6468036530 + ... + 6468038403.

It is an arithmetic number, because the mean of its divisors is an integer number (3033509572023).

Almost surely, 2^{12121102212221} is an apocalyptic number.

It is an amenable number.

12121102212221 is a deficient number, since it is larger than the sum of its proper divisors (12936075871).

12121102212221 is an equidigital number, since it uses as much as digits as its factorization.

12121102212221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12936075870.

The product of its (nonzero) digits is 128, while the sum is 20.

Adding to 12121102212221 its reverse (12221220112121), we get a palindrome (24342322324342).

The spelling of 12121102212221 in words is "twelve trillion, one hundred twenty-one billion, one hundred two million, two hundred twelve thousand, two hundred twenty-one".