668687020171 has 4 divisors (see below), whose sum is σ = 668763563992. Its totient is φ = 668610476352.

The previous prime is 668687020159. The next prime is 668687020181. The reversal of 668687020171 is 171020786866.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 171020786866 = 2 ⋅85510393433.

It is a cyclic number.

It is not a de Polignac number, because 668687020171 - 2¹⁷ = 668686889099 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (668687020181) 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 3 ways as a sum of consecutive naturals, for example, 38258805 + ... + 38276278.

It is an arithmetic number, because the mean of its divisors is an integer number (167190890998).

Almost surely, 2^668687020171 is an apocalyptic number.

668687020171 is a deficient number, since it is larger than the sum of its proper divisors (76543821).

668687020171 is an equidigital number, since it uses as much as digits as its factorization.

668687020171 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76543820.

The product of its (nonzero) digits is 1354752, while the sum is 52.

The spelling of 668687020171 in words is "six hundred sixty-eight billion, six hundred eighty-seven million, twenty thousand, one hundred seventy-one".