6646779497 has 4 divisors (see below), whose sum is σ = 6875978820. Its totient is φ = 6417580176.

The previous prime is 6646779479. The next prime is 6646779511. The reversal of 6646779497 is 7949776466.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1846506841 + 4800272656 = 42971^2 + 69284^2 .

It is a cyclic number.

It is not a de Polignac number, because 6646779497 - 2¹⁴ = 6646763113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6646779437) 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 in 3 ways as a sum of consecutive naturals, for example, 114599618 + ... + 114599675.

It is an arithmetic number, because the mean of its divisors is an integer number (1718994705).

Almost surely, 2^6646779497 is an apocalyptic number.

It is an amenable number.

6646779497 is a deficient number, since it is larger than the sum of its proper divisors (229199323).

6646779497 is a wasteful number, since it uses less digits than its factorization.

6646779497 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 229199322.

The product of its digits is 96018048, while the sum is 65.

The square root of 6646779497 is about 81527.7835893998. The cubic root of 6646779497 is about 1880.1987394586.

The spelling of 6646779497 in words is "six billion, six hundred forty-six million, seven hundred seventy-nine thousand, four hundred ninety-seven".