6639109 has 2 divisors, whose sum is σ = 6639110. Its totient is φ = 6639108.

The previous prime is 6639107. The next prime is 6639119. The reversal of 6639109 is 9019366.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5536609 + 1102500 = 2353^2 + 1050^2 .

It is a cyclic number.

It is not a de Polignac number, because 6639109 - 2¹ = 6639107 is a prime.

Together with 6639107, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6639107) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3319554 + 3319555.

It is an arithmetic number, because the mean of its divisors is an integer number (3319555).

Almost surely, 2^6639109 is an apocalyptic number.

It is an amenable number.

6639109 is a deficient number, since it is larger than the sum of its proper divisors (1).

6639109 is an equidigital number, since it uses as much as digits as its factorization.

6639109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8748, while the sum is 34.

The square root of 6639109 is about 2576.6468520152. The cubic root of 6639109 is about 187.9475200582.

The spelling of 6639109 in words is "six million, six hundred thirty-nine thousand, one hundred nine".