6646451666 has 16 divisors (see below), whose sum is σ = 10004244120. Its totient is φ = 3311719680.

The previous prime is 6646451641. The next prime is 6646451743. The reversal of 6646451666 is 6661546466.

It can be written as a sum of positive squares in 4 ways, for example, as 5661810025 + 984641641 = 75245^2 + 31379^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1055720 + ... + 1061996.

Almost surely, 2^6646451666 is an apocalyptic number.

6646451666 is a deficient number, since it is larger than the sum of its proper divisors (3357792454).

6646451666 is a wasteful number, since it uses less digits than its factorization.

6646451666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8029.

The product of its digits is 3732480, while the sum is 50.

The square root of 6646451666 is about 81525.7730168810. The cubic root of 6646451666 is about 1880.1678273671.

The spelling of 6646451666 in words is "six billion, six hundred forty-six million, four hundred fifty-one thousand, six hundred sixty-six".