6561886878755 has 16 divisors (see below), whose sum is σ = 8480445143520. Its totient is φ = 4845433506048.

The previous prime is 6561886878749. The next prime is 6561886878763. The reversal of 6561886878755 is 5578786881656.

It is a cyclic number.

It is not a de Polignac number, because 6561886878755 - 2⁶ = 6561886878691 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6561886878755.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1597157 + ... + 3959126.

It is an arithmetic number, because the mean of its divisors is an integer number (530027821470).

Almost surely, 2^{6561886878755} is an apocalyptic number.

6561886878755 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

6561886878755 is a deficient number, since it is larger than the sum of its proper divisors (1918558264765).

6561886878755 is a wasteful number, since it uses less digits than its factorization.

6561886878755 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5574470.

The product of its digits is 5419008000, while the sum is 80.

The spelling of 6561886878755 in words is "six trillion, five hundred sixty-one billion, eight hundred eighty-six million, eight hundred seventy-eight thousand, seven hundred fifty-five".