12644221 has 4 divisors (see below), whose sum is σ = 12660444. Its totient is φ = 12628000.

The previous prime is 12644213. The next prime is 12644237. The reversal of 12644221 is 12244621.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12244621 = 461 ⋅26561.

It can be written as a sum of positive squares in 2 ways, for example, as 9180900 + 3463321 = 3030^2 + 1861^2 .

It is a cyclic number.

It is not a de Polignac number, because 12644221 - 2³ = 12644213 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12644192 and 12644201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12644201) 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, 6880 + ... + 8521.

It is an arithmetic number, because the mean of its divisors is an integer number (3165111).

Almost surely, 2^12644221 is an apocalyptic number.

It is an amenable number.

12644221 is a deficient number, since it is larger than the sum of its proper divisors (16223).

12644221 is an equidigital number, since it uses as much as digits as its factorization.

12644221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16222.

The product of its digits is 768, while the sum is 22.

The square root of 12644221 is about 3555.8713418795. The cubic root of 12644221 is about 232.9685836304.

Adding to 12644221 its reverse (12244621), we get a palindrome (24888842).

The spelling of 12644221 in words is "twelve million, six hundred forty-four thousand, two hundred twenty-one".