6663639 has 8 divisors (see below), whose sum is σ = 8968320. Its totient is φ = 4400696.

The previous prime is 6663617. The next prime is 6663647. The reversal of 6663639 is 9363666.

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

It is not a de Polignac number, because 6663639 - 2⁷ = 6663511 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 6663597 and 6663606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6663539) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10059 + ... + 10700.

It is an arithmetic number, because the mean of its divisors is an integer number (1121040).

Almost surely, 2^6663639 is an apocalyptic number.

6663639 is a deficient number, since it is larger than the sum of its proper divisors (2304681).

6663639 is a wasteful number, since it uses less digits than its factorization.

6663639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20869.

The product of its digits is 104976, while the sum is 39.

The square root of 6663639 is about 2581.4025257600. The cubic root of 6663639 is about 188.1787100278.

The spelling of 6663639 in words is "six million, six hundred sixty-three thousand, six hundred thirty-nine".