6399688 has 8 divisors (see below), whose sum is σ = 11999430. Its totient is φ = 3199840.

The previous prime is 6399683. The next prime is 6399689. The reversal of 6399688 is 8869936.

It can be written as a sum of positive squares in only one way, i.e., 6360484 + 39204 = 2522^2 + 198^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (6399683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 399973 + ... + 399988.

Almost surely, 2^6399688 is an apocalyptic number.

It is an amenable number.

6399688 is a deficient number, since it is larger than the sum of its proper divisors (5599742).

6399688 is a wasteful number, since it uses less digits than its factorization.

6399688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 799967 (or 799963 counting only the distinct ones).

The product of its digits is 559872, while the sum is 49.

The square root of 6399688 is about 2529.7604629688. The cubic root of 6399688 is about 185.6605362627.

The spelling of 6399688 in words is "six million, three hundred ninety-nine thousand, six hundred eighty-eight".