6399535943 has 4 divisors (see below), whose sum is σ = 6401225160. Its totient is φ = 6397846728.

The previous prime is 6399535927. The next prime is 6399535973. The reversal of 6399535943 is 3495359936.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 6399535943 - 2⁴ = 6399535927 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6399535903) 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 in 3 ways as a sum of consecutive naturals, for example, 838913 + ... + 846506.

It is an arithmetic number, because the mean of its divisors is an integer number (1600306290).

Almost surely, 2^6399535943 is an apocalyptic number.

6399535943 is a deficient number, since it is larger than the sum of its proper divisors (1689217).

6399535943 is a wasteful number, since it uses less digits than its factorization.

6399535943 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1689216.

The product of its digits is 11809800, while the sum is 56.

The square root of 6399535943 is about 79997.0995911727. The cubic root of 6399535943 is about 1856.5906581565.

The spelling of 6399535943 in words is "six billion, three hundred ninety-nine million, five hundred thirty-five thousand, nine hundred forty-three".