6615515666 has 8 divisors (see below), whose sum is σ = 9989873100. Its totient is φ = 3285557968.

The previous prime is 6615515653. The next prime is 6615515671. The reversal of 6615515666 is 6665155166.

It can be written as a sum of positive squares in 2 ways, for example, as 5794406641 + 821109025 = 76121^2 + 28655^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 6615515666.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11099561 + ... + 11100156.

Almost surely, 2^6615515666 is an apocalyptic number.

6615515666 is a deficient number, since it is larger than the sum of its proper divisors (3374357434).

6615515666 is a wasteful number, since it uses less digits than its factorization.

6615515666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22199868.

The product of its digits is 972000, while the sum is 47.

The square root of 6615515666 is about 81335.8203130699. The cubic root of 6615515666 is about 1877.2462008121.

The spelling of 6615515666 in words is "six billion, six hundred fifteen million, five hundred fifteen thousand, six hundred sixty-six".