6640936909 has 2 divisors, whose sum is σ = 6640936910. Its totient is φ = 6640936908.

The previous prime is 6640936903. The next prime is 6640936921. The reversal of 6640936909 is 9096390466.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3323522500 + 3317414409 = 57650^2 + 57597^2 .

It is a cyclic number.

It is not a de Polignac number, because 6640936909 - 2⁷ = 6640936781 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6640936903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3320468454 + 3320468455.

It is an arithmetic number, because the mean of its divisors is an integer number (3320468455).

Almost surely, 2^6640936909 is an apocalyptic number.

It is an amenable number.

6640936909 is a deficient number, since it is larger than the sum of its proper divisors (1).

6640936909 is an equidigital number, since it uses as much as digits as its factorization.

6640936909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1889568, while the sum is 52.

The square root of 6640936909 is about 81491.9438288227. The cubic root of 6640936909 is about 1879.6476732427.

The spelling of 6640936909 in words is "six billion, six hundred forty million, nine hundred thirty-six thousand, nine hundred nine".