12438721 has 2 divisors, whose sum is σ = 12438722. Its totient is φ = 12438720.

The previous prime is 12438707. The next prime is 12438737. The reversal of 12438721 is 12783421.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6864400 + 5574321 = 2620^2 + 2361^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12438721 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 12438721.

It is not a weakly prime, because it can be changed into another prime (12438121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6219360 + 6219361.

It is an arithmetic number, because the mean of its divisors is an integer number (6219361).

Almost surely, 2^12438721 is an apocalyptic number.

It is an amenable number.

12438721 is a deficient number, since it is larger than the sum of its proper divisors (1).

12438721 is an equidigital number, since it uses as much as digits as its factorization.

12438721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2688, while the sum is 28.

The square root of 12438721 is about 3526.8570994584. The cubic root of 12438721 is about 231.6995777016.

The spelling of 12438721 in words is "twelve million, four hundred thirty-eight thousand, seven hundred twenty-one".