6649664771 has 2 divisors, whose sum is σ = 6649664772. Its totient is φ = 6649664770.

The previous prime is 6649664761. The next prime is 6649664831. The reversal of 6649664771 is 1774669466.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6649664771 - 2¹⁴ = 6649648387 is a prime.

It is not a weakly prime, because it can be changed into another prime (6649664761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3324832385 + 3324832386.

It is an arithmetic number, because the mean of its divisors is an integer number (3324832386).

Almost surely, 2^6649664771 is an apocalyptic number.

6649664771 is a deficient number, since it is larger than the sum of its proper divisors (1).

6649664771 is an equidigital number, since it uses as much as digits as its factorization.

6649664771 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9144576, while the sum is 56.

The square root of 6649664771 is about 81545.4767047198. The cubic root of 6649664771 is about 1880.4707560932.

The spelling of 6649664771 in words is "six billion, six hundred forty-nine million, six hundred sixty-four thousand, seven hundred seventy-one".