6639375 has 20 divisors (see below), whose sum is σ = 11065208. Its totient is φ = 3540000.

The previous prime is 6639349. The next prime is 6639377. The reversal of 6639375 is 5739366.

It is not a de Polignac number, because 6639375 - 2⁸ = 6639119 is a prime.

It is a d-powerful number, because it can be written as 6 + 6⁸ + 3¹⁰ + 9² + 3¹⁴ + 7⁶ + 5 .

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6639377) 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 19 ways as a sum of consecutive naturals, for example, 105 + ... + 3645.

Almost surely, 2^6639375 is an apocalyptic number.

6639375 is a deficient number, since it is larger than the sum of its proper divisors (4425833).

6639375 is an equidigital number, since it uses as much as digits as its factorization.

6639375 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3564 (or 3549 counting only the distinct ones).

The product of its digits is 102060, while the sum is 39.

The square root of 6639375 is about 2576.6984689715. The cubic root of 6639375 is about 187.9500301024.

Subtracting from 6639375 its reverse (5739366), we obtain a palindrome (900009).

The spelling of 6639375 in words is "six million, six hundred thirty-nine thousand, three hundred seventy-five".