6646451665 has 16 divisors (see below), whose sum is σ = 9651318912. Its totient is φ = 4289474304.

The previous prime is 6646451641. The next prime is 6646451743. The reversal of 6646451665 is 5661546466.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 6646451665 - 2⁵ = 6646451633 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5584659 + ... + 5585848.

It is an arithmetic number, because the mean of its divisors is an integer number (603207432).

Almost surely, 2^6646451665 is an apocalyptic number.

It is an amenable number.

6646451665 is a deficient number, since it is larger than the sum of its proper divisors (3004867247).

6646451665 is a wasteful number, since it uses less digits than its factorization.

6646451665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11170536.

The product of its digits is 3110400, while the sum is 49.

The square root of 6646451665 is about 81525.7730107480. The cubic root of 6646451665 is about 1880.1678272728.

The spelling of 6646451665 in words is "six billion, six hundred forty-six million, four hundred fifty-one thousand, six hundred sixty-five".