66561584481 has 24 divisors (see below), whose sum is σ = 110906362944. Its totient is φ = 37679718240.

The previous prime is 66561584449. The next prime is 66561584519. The reversal of 66561584481 is 18448516566.

It is a happy number.

66561584481 is a `hidden beast` number, since 6 + 6 + 5 + 6 + 158 + 4 + 481 = 666.

It is not a de Polignac number, because 66561584481 - 2⁵ = 66561584449 is a prime.

It is a super-2 number, since 2×66561584481² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (66561584281) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4930330 + ... + 4943811.

It is an arithmetic number, because the mean of its divisors is an integer number (4621098456).

Almost surely, 2^66561584481 is an apocalyptic number.

It is an amenable number.

66561584481 is a deficient number, since it is larger than the sum of its proper divisors (44344778463).

66561584481 is a wasteful number, since it uses less digits than its factorization.

66561584481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9874261 (or 9874258 counting only the distinct ones).

The product of its digits is 5529600, while the sum is 54.

The spelling of 66561584481 in words is "sixty-six billion, five hundred sixty-one million, five hundred eighty-four thousand, four hundred eighty-one".