12172321 has 4 divisors (see below), whose sum is σ = 13911232. Its totient is φ = 10433412.

The previous prime is 12172309. The next prime is 12172327. The reversal of 12172321 is 12327121.

12172321 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 a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12327121 = 3511².

It is a cyclic number.

It is not a de Polignac number, because 12172321 - 2¹¹ = 12170273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12172327) 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, 869445 + ... + 869458.

It is an arithmetic number, because the mean of its divisors is an integer number (3477808).

Almost surely, 2^12172321 is an apocalyptic number.

It is an amenable number.

12172321 is a deficient number, since it is larger than the sum of its proper divisors (1738911).

12172321 is an equidigital number, since it uses as much as digits as its factorization.

12172321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1738910.

The product of its digits is 168, while the sum is 19.

The square root of 12172321 is about 3488.8853520860. The cubic root of 12172321 is about 230.0335237839.

Adding to 12172321 its reverse (12327121), we get a palindrome (24499442).

The spelling of 12172321 in words is "twelve million, one hundred seventy-two thousand, three hundred twenty-one".