6399906 has 8 divisors (see below), whose sum is σ = 12799824. Its totient is φ = 2133300.

The previous prime is 6399889. The next prime is 6399917. The reversal of 6399906 is 6099936.

It is a sphenic number, since it is the product of 3 distinct primes.

6399906 is an admirable number.

It is an Ulam number.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 533320 + ... + 533331.

It is an arithmetic number, because the mean of its divisors is an integer number (1599978).

Almost surely, 2^6399906 is an apocalyptic number.

6399906 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6399906 is a wasteful number, since it uses less digits than its factorization.

6399906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1066656.

The product of its (nonzero) digits is 78732, while the sum is 42.

The square root of 6399906 is about 2529.8035496852. The cubic root of 6399906 is about 185.6626443622.

The spelling of 6399906 in words is "six million, three hundred ninety-nine thousand, nine hundred six".