399679844689 has 2 divisors, whose sum is σ = 399679844690. Its totient is φ = 399679844688.

The previous prime is 399679844653. The next prime is 399679844723. The reversal of 399679844689 is 986448976993.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 354302324289 + 45377520400 = 595233^2 + 213020^2 .

It is a cyclic number.

It is not a de Polignac number, because 399679844689 - 2⁹ = 399679844177 is a prime.

It is not a weakly prime, because it can be changed into another prime (399679844189) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199839922344 + 199839922345.

It is an arithmetic number, because the mean of its divisors is an integer number (199839922345).

Almost surely, 2^399679844689 is an apocalyptic number.

It is an amenable number.

399679844689 is a deficient number, since it is larger than the sum of its proper divisors (1).

399679844689 is an equidigital number, since it uses as much as digits as its factorization.

399679844689 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5079158784, while the sum is 82.

The spelling of 399679844689 in words is "three hundred ninety-nine billion, six hundred seventy-nine million, eight hundred forty-four thousand, six hundred eighty-nine".