12724021 has 2 divisors, whose sum is σ = 12724022. Its totient is φ = 12724020.

The previous prime is 12724009. The next prime is 12724027. The reversal of 12724021 is 12042721.

It is a happy number.

12724021 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12327121 + 396900 = 3511^2 + 630^2 .

It is an emirp because it is prime and its reverse (12042721) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12724021 - 2⁹ = 12723509 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 12724021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12724027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6362010 + 6362011.

It is an arithmetic number, because the mean of its divisors is an integer number (6362011).

Almost surely, 2^12724021 is an apocalyptic number.

It is an amenable number.

12724021 is a deficient number, since it is larger than the sum of its proper divisors (1).

12724021 is an equidigital number, since it uses as much as digits as its factorization.

12724021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 224, while the sum is 19.

The square root of 12724021 is about 3567.0745716904. The cubic root of 12724021 is about 233.4576586881.

Adding to 12724021 its reverse (12042721), we get a palindrome (24766742).

The spelling of 12724021 in words is "twelve million, seven hundred twenty-four thousand, twenty-one".