66551666515611 has 48 divisors (see below), whose sum is σ = 95481029726208. Its totient is φ = 41218907200000.

The previous prime is 66551666515561. The next prime is 66551666515613. The reversal of 66551666515611 is 11651566615566.

It is a happy number.

66551666515611 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 66551666515611 - 2⁷ = 66551666515483 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66551666515613) 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 47 ways as a sum of consecutive naturals, for example, 82425361 + ... + 83228861.

It is an arithmetic number, because the mean of its divisors is an integer number (1989188119296).

Almost surely, 2^{66551666515611} is an apocalyptic number.

66551666515611 is a deficient number, since it is larger than the sum of its proper divisors (28929363210597).

66551666515611 is a wasteful number, since it uses less digits than its factorization.

66551666515611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 804772 (or 804755 counting only the distinct ones).

The product of its digits is 29160000, while the sum is 60.

The spelling of 66551666515611 in words is "sixty-six trillion, five hundred fifty-one billion, six hundred sixty-six million, five hundred fifteen thousand, six hundred eleven".