6640936849 has 2 divisors, whose sum is σ = 6640936850. Its totient is φ = 6640936848.

The previous prime is 6640936781. The next prime is 6640936853. The reversal of 6640936849 is 9486390466.

6640936849 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4046868225 + 2594068624 = 63615^2 + 50932^2 .

It is a cyclic number.

It is not a de Polignac number, because 6640936849 - 2¹¹ = 6640934801 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6640936849.

It is not a weakly prime, because it can be changed into another prime (6640936949) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3320468424 + 3320468425.

It is an arithmetic number, because the mean of its divisors is an integer number (3320468425).

Almost surely, 2^6640936849 is an apocalyptic number.

It is an amenable number.

6640936849 is a deficient number, since it is larger than the sum of its proper divisors (1).

6640936849 is an equidigital number, since it uses as much as digits as its factorization.

6640936849 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6718464, while the sum is 55.

The square root of 6640936849 is about 81491.9434606882. The cubic root of 6640936849 is about 1879.6476675819.

The spelling of 6640936849 in words is "six billion, six hundred forty million, nine hundred thirty-six thousand, eight hundred forty-nine".