6638939 has 8 divisors (see below), whose sum is σ = 6806160. Its totient is φ = 6473376.

The previous prime is 6638911. The next prime is 6638953. The reversal of 6638939 is 9398366.

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

It is a cyclic number.

It is not a de Polignac number, because 6638939 - 2²⁰ = 5590363 is a prime.

It is a super-2 number, since 2×6638939² = 88151022091442, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 6638939.

It is not an unprimeable number, because it can be changed into a prime (6638339) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 11864 + ... + 12410.

It is an arithmetic number, because the mean of its divisors is an integer number (850770).

Almost surely, 2^6638939 is an apocalyptic number.

6638939 is a deficient number, since it is larger than the sum of its proper divisors (167221).

6638939 is a wasteful number, since it uses less digits than its factorization.

6638939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 829.

The product of its digits is 209952, while the sum is 44.

The square root of 6638939 is about 2576.6138631933. The cubic root of 6638939 is about 187.9459158594.

The spelling of 6638939 in words is "six million, six hundred thirty-eight thousand, nine hundred thirty-nine".