12213121 has 4 divisors (see below), whose sum is σ = 12511044. Its totient is φ = 11915200.

The previous prime is 12213109. The next prime is 12213127. The reversal of 12213121 is 12131221.

12213121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12131221 = 67 ⋅181063.

It can be written as a sum of positive squares in 2 ways, for example, as 923521 + 11289600 = 961^2 + 3360^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12213121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12213127) 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, 148900 + ... + 148981.

It is an arithmetic number, because the mean of its divisors is an integer number (3127761).

Almost surely, 2^12213121 is an apocalyptic number.

It is an amenable number.

12213121 is a deficient number, since it is larger than the sum of its proper divisors (297923).

12213121 is an equidigital number, since it uses as much as digits as its factorization.

12213121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 297922.

The product of its digits is 24, while the sum is 13.

The square root of 12213121 is about 3494.7276002573. The cubic root of 12213121 is about 230.2902510776.

Adding to 12213121 its reverse (12131221), we get a palindrome (24344342).

It can be divided in two parts, 1 and 2213121, that added together give a palindrome (2213122).

The spelling of 12213121 in words is "twelve million, two hundred thirteen thousand, one hundred twenty-one".