6639998 has 8 divisors (see below), whose sum is σ = 10057008. Its totient is φ = 3287664.

The previous prime is 6639989. The next prime is 6640003. The reversal of 6639998 is 8999366.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15911 + ... + 16322.

It is an arithmetic number, because the mean of its divisors is an integer number (1257126).

Almost surely, 2^6639998 is an apocalyptic number.

6639998 is a deficient number, since it is larger than the sum of its proper divisors (3417010).

6639998 is a wasteful number, since it uses less digits than its factorization.

6639998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32338.

The product of its digits is 629856, while the sum is 50.

The square root of 6639998 is about 2576.8193572697. The cubic root of 6639998 is about 187.9559086280.

The spelling of 6639998 in words is "six million, six hundred thirty-nine thousand, nine hundred ninety-eight".