668756784171 has 32 divisors (see below), whose sum is σ = 1092660848640. Its totient is φ = 355114745856.

The previous prime is 668756784149. The next prime is 668756784257. The reversal of 668756784171 is 171487657866.

It is not a de Polignac number, because 668756784171 - 2⁷ = 668756784043 is a prime.

It is not an unprimeable number, because it can be changed into a prime (668756734171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11827926 + ... + 11884331.

It is an arithmetic number, because the mean of its divisors is an integer number (34145651520).

Almost surely, 2^668756784171 is an apocalyptic number.

668756784171 is a deficient number, since it is larger than the sum of its proper divisors (423904064469).

668756784171 is a wasteful number, since it uses less digits than its factorization.

668756784171 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23712363.

The product of its digits is 94832640, while the sum is 66.

The spelling of 668756784171 in words is "six hundred sixty-eight billion, seven hundred fifty-six million, seven hundred eighty-four thousand, one hundred seventy-one".