6561759878 has 16 divisors (see below), whose sum is σ = 10201556880. Its totient is φ = 3161674656.

The previous prime is 6561759851. The next prime is 6561759887. The reversal of 6561759878 is 8789571656.

It is a self number, because there is not a number n which added to its sum of digits gives 6561759878.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 77825 + ... + 138492.

It is an arithmetic number, because the mean of its divisors is an integer number (637597305).

Almost surely, 2^6561759878 is an apocalyptic number.

6561759878 is a deficient number, since it is larger than the sum of its proper divisors (3639797002).

6561759878 is a wasteful number, since it uses less digits than its factorization.

6561759878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 216871.

The product of its digits is 25401600, while the sum is 62.

The square root of 6561759878 is about 81004.6904691327. The cubic root of 6561759878 is about 1872.1477109305.

The spelling of 6561759878 in words is "six billion, five hundred sixty-one million, seven hundred fifty-nine thousand, eight hundred seventy-eight".