66561364611 has 24 divisors (see below), whose sum is σ = 109945165824. Its totient is φ = 38012189040.

The previous prime is 66561364577. The next prime is 66561364619. The reversal of 66561364611 is 11646316566.

66561364611 is a `hidden beast` number, since 6 + 6 + 56 + 136 + 461 + 1 = 666.

It is not a de Polignac number, because 66561364611 - 2¹⁷ = 66561233539 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66561364619) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 211875 + ... + 421916.

It is an arithmetic number, because the mean of its divisors is an integer number (4581048576).

Almost surely, 2^66561364611 is an apocalyptic number.

66561364611 is a deficient number, since it is larger than the sum of its proper divisors (43383801213).

66561364611 is a wasteful number, since it uses less digits than its factorization.

66561364611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 635471 (or 635468 counting only the distinct ones).

The product of its digits is 466560, while the sum is 45.

The spelling of 66561364611 in words is "sixty-six billion, five hundred sixty-one million, three hundred sixty-four thousand, six hundred eleven".