66512105510721 has 8 divisors (see below), whose sum is σ = 95504561759040. Its totient is φ = 40930526468112.

The previous prime is 66512105510707. The next prime is 66512105510723. The reversal of 66512105510721 is 12701550121566.

It is a happy number.

66512105510721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 66512105510721 - 2⁵ = 66512105510689 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66512105510723) 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 7 ways as a sum of consecutive naturals, for example, 852719301381 + ... + 852719301458.

It is an arithmetic number, because the mean of its divisors is an integer number (11938070219880).

Almost surely, 2^{66512105510721} is an apocalyptic number.

It is an amenable number.

66512105510721 is a deficient number, since it is larger than the sum of its proper divisors (28992456248319).

66512105510721 is a wasteful number, since it uses less digits than its factorization.

66512105510721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1705438602855.

The product of its (nonzero) digits is 126000, while the sum is 42.

The spelling of 66512105510721 in words is "sixty-six trillion, five hundred twelve billion, one hundred five million, five hundred ten thousand, seven hundred twenty-one".