6640566613 has 8 divisors (see below), whose sum is σ = 6654907800. Its totient is φ = 6626239488.

The previous prime is 6640566607. The next prime is 6640566659. The reversal of 6640566613 is 3166650466.

It can be written as a sum of positive squares in 4 ways, for example, as 1316383524 + 5324183089 = 36282^2 + 72967^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6640566613 - 2¹⁷ = 6640435541 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 6640566613.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6644566613) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2067753 + ... + 2070961.

It is an arithmetic number, because the mean of its divisors is an integer number (831863475).

Almost surely, 2^6640566613 is an apocalyptic number.

It is an amenable number.

6640566613 is a deficient number, since it is larger than the sum of its proper divisors (14341187).

6640566613 is a wasteful number, since it uses less digits than its factorization.

6640566613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7031.

The product of its (nonzero) digits is 466560, while the sum is 43.

The square root of 6640566613 is about 81489.6718179672. The cubic root of 6640566613 is about 1879.6127364579.

The spelling of 6640566613 in words is "six billion, six hundred forty million, five hundred sixty-six thousand, six hundred thirteen".