6561205505604 has 36 divisors (see below), whose sum is σ = 16585474938396. Its totient is φ = 2187041407488.

The previous prime is 6561205505599. The next prime is 6561205505633. The reversal of 6561205505604 is 4065055021656.

6561205505604 is a `hidden beast` number, since 6 + 5 + 61 + 20 + 5 + 5 + 0 + 560 + 4 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1005002240004 + 5556203265600 = 1002498^2 + 2357160^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a self number, because there is not a number n which added to its sum of digits gives 6561205505604.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1930972 + ... + 4105004.

Almost surely, 2^{6561205505604} is an apocalyptic number.

It is an amenable number.

6561205505604 is an abundant number, since it is smaller than the sum of its proper divisors (10024269432792).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6561205505604 is a wasteful number, since it uses less digits than its factorization.

6561205505604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2257876 (or 2257871 counting only the distinct ones).

The product of its (nonzero) digits is 1080000, while the sum is 45.

The spelling of 6561205505604 in words is "six trillion, five hundred sixty-one billion, two hundred five million, five hundred five thousand, six hundred four".