12172221 has 32 divisors (see below), whose sum is σ = 19941120. Its totient is φ = 7299072.

The previous prime is 12172219. The next prime is 12172253. The reversal of 12172221 is 12227121.

It is a happy number.

It is not a de Polignac number, because 12172221 - 2¹ = 12172219 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 12172194 and 12172203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12172271) 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 31 ways as a sum of consecutive naturals, for example, 9981 + ... + 11133.

It is an arithmetic number, because the mean of its divisors is an integer number (623160).

Almost surely, 2^12172221 is an apocalyptic number.

It is an amenable number.

12172221 is a deficient number, since it is larger than the sum of its proper divisors (7768899).

12172221 is a wasteful number, since it uses less digits than its factorization.

12172221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1202 (or 1196 counting only the distinct ones).

The product of its digits is 112, while the sum is 18.

The square root of 12172221 is about 3488.8710208318. The cubic root of 12172221 is about 230.0328938461.

Adding to 12172221 its reverse (12227121), we get a palindrome (24399342).

The spelling of 12172221 in words is "twelve million, one hundred seventy-two thousand, two hundred twenty-one".