12321721 has 4 divisors (see below), whose sum is σ = 12857472. Its totient is φ = 11785972.

The previous prime is 12321713. The next prime is 12321733. The reversal of 12321721 is 12712321.

12321721 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.

It is a cyclic number.

It is not a de Polignac number, because 12321721 - 2³ = 12321713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12321121) 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, 267841 + ... + 267886.

It is an arithmetic number, because the mean of its divisors is an integer number (3214368).

Almost surely, 2^12321721 is an apocalyptic number.

It is an amenable number.

12321721 is a deficient number, since it is larger than the sum of its proper divisors (535751).

12321721 is an equidigital number, since it uses as much as digits as its factorization.

12321721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 535750.

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

The square root of 12321721 is about 3510.2309040859. The cubic root of 12321721 is about 230.9708239483.

The spelling of 12321721 in words is "twelve million, three hundred twenty-one thousand, seven hundred twenty-one".