6399999959 has 2 divisors, whose sum is σ = 6399999960. Its totient is φ = 6399999958.

The previous prime is 6399999953. The next prime is 6400000007. The reversal of 6399999959 is 9599999936.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6399999959 - 2⁴ = 6399999943 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6399999959.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6399999953) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3199999979 + 3199999980.

It is an arithmetic number, because the mean of its divisors is an integer number (3199999980).

Almost surely, 2^6399999959 is an apocalyptic number.

6399999959 is a deficient number, since it is larger than the sum of its proper divisors (1).

6399999959 is an equidigital number, since it uses as much as digits as its factorization.

6399999959 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 430467210, while the sum is 77.

The square root of 6399999959 is about 79999.9997437500. Note that the first 3 decimals coincide. The cubic root of 6399999959 is about 1856.6355294804.

The spelling of 6399999959 in words is "six billion, three hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred fifty-nine".