6639997 has 16 divisors (see below), whose sum is σ = 8249472. Its totient is φ = 5204160.

The previous prime is 6639989. The next prime is 6640003. The reversal of 6639997 is 7999366.

It is not a de Polignac number, because 6639997 - 2³ = 6639989 is a prime.

It is a d-powerful number, because it can be written as 6³ + 6⁸ + 3¹⁴ + 9⁵ + 9⁵ + 9⁵ + 7² .

It is a self number, because there is not a number n which added to its sum of digits gives 6639997.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6639907) 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 15 ways as a sum of consecutive naturals, for example, 11643 + ... + 12199.

It is an arithmetic number, because the mean of its divisors is an integer number (515592).

Almost surely, 2^6639997 is an apocalyptic number.

It is an amenable number.

6639997 is a deficient number, since it is larger than the sum of its proper divisors (1609475).

6639997 is a wasteful number, since it uses less digits than its factorization.

6639997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 708.

The product of its digits is 551124, while the sum is 49.

The square root of 6639997 is about 2576.8191632321. The cubic root of 6639997 is about 187.9558991924.

The spelling of 6639997 in words is "six million, six hundred thirty-nine thousand, nine hundred ninety-seven".