6561333664 has 24 divisors (see below), whose sum is σ = 12928637988. Its totient is φ = 3277870080.

The previous prime is 6561333643. The next prime is 6561333673. The reversal of 6561333664 is 4663331656.

It can be written as a sum of positive squares in 2 ways, for example, as 6037290000 + 524043664 = 77700^2 + 22892^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 6561333664.

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, 49017 + ... + 124600.

Almost surely, 2^6561333664 is an apocalyptic number.

It is an amenable number.

6561333664 is a deficient number, since it is larger than the sum of its proper divisors (6367304324).

6561333664 is a wasteful number, since it uses less digits than its factorization.

6561333664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174808 (or 174800 counting only the distinct ones).

The product of its digits is 699840, while the sum is 43.

The square root of 6561333664 is about 81002.0596281354. The cubic root of 6561333664 is about 1872.1071754209.

The spelling of 6561333664 in words is "six billion, five hundred sixty-one million, three hundred thirty-three thousand, six hundred sixty-four".