6646665543 has 16 divisors (see below), whose sum is σ = 10179671040. Its totient is φ = 3778812576.

The previous prime is 6646665503. The next prime is 6646665551. The reversal of 6646665543 is 3455666466.

It is not a de Polignac number, because 6646665543 - 2¹⁸ = 6646403399 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6646665503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 799183 + ... + 807456.

It is an arithmetic number, because the mean of its divisors is an integer number (636229440).

Almost surely, 2^6646665543 is an apocalyptic number.

6646665543 is a deficient number, since it is larger than the sum of its proper divisors (3533005497).

6646665543 is a wasteful number, since it uses less digits than its factorization.

6646665543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1606846.

The product of its digits is 9331200, while the sum is 51.

The square root of 6646665543 is about 81527.0847203554. The cubic root of 6646665543 is about 1880.1879945361.

The spelling of 6646665543 in words is "six billion, six hundred forty-six million, six hundred sixty-five thousand, five hundred forty-three".