6399686 has 4 divisors (see below), whose sum is σ = 9599532. Its totient is φ = 3199842.

The previous prime is 6399683. The next prime is 6399689. The reversal of 6399686 is 6869936.

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

It is an interprime number because it is at equal distance from previous prime (6399683) and next prime (6399689).

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 6399686.

It is a congruent number.

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

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1599920 + ... + 1599923.

It is an arithmetic number, because the mean of its divisors is an integer number (2399883).

Almost surely, 2^6399686 is an apocalyptic number.

6399686 is a deficient number, since it is larger than the sum of its proper divisors (3199846).

6399686 is a wasteful number, since it uses less digits than its factorization.

6399686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3199845.

The product of its digits is 419904, while the sum is 47.

The square root of 6399686 is about 2529.7600676744. The cubic root of 6399686 is about 185.6605169222.

The spelling of 6399686 in words is "six million, three hundred ninety-nine thousand, six hundred eighty-six".