9399438721 has 2 divisors, whose sum is σ = 9399438722. Its totient is φ = 9399438720.

The previous prime is 9399438709. The next prime is 9399438743. The reversal of 9399438721 is 1278349939.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5993082225 + 3406356496 = 77415^2 + 58364^2 .

It is a cyclic number.

It is not a de Polignac number, because 9399438721 - 2⁵ = 9399438689 is a prime.

It is not a weakly prime, because it can be changed into another prime (9399438701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4699719360 + 4699719361.

It is an arithmetic number, because the mean of its divisors is an integer number (4699719361).

Almost surely, 2^9399438721 is an apocalyptic number.

It is an amenable number.

9399438721 is a deficient number, since it is larger than the sum of its proper divisors (1).

9399438721 is an equidigital number, since it uses as much as digits as its factorization.

9399438721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2939328, while the sum is 55.

The square root of 9399438721 is about 96950.7025296877. The cubic root of 9399438721 is about 2110.4122882046.

The spelling of 9399438721 in words is "nine billion, three hundred ninety-nine million, four hundred thirty-eight thousand, seven hundred twenty-one".