666171171667 has 4 divisors (see below), whose sum is σ = 667753526416. Its totient is φ = 664588816920.

The previous prime is 666171171661. The next prime is 666171171671. The reversal of 666171171667 is 766171171666.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 666171171667 - 2¹¹ = 666171169619 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666171171661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 791176743 + ... + 791177584.

It is an arithmetic number, because the mean of its divisors is an integer number (166938381604).

Almost surely, 2^666171171667 is an apocalyptic number.

666171171667 is a deficient number, since it is larger than the sum of its proper divisors (1582354749).

666171171667 is a wasteful number, since it uses less digits than its factorization.

666171171667 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1582354748.

The product of its digits is 2667168, while the sum is 55.

Subtracting 666171171667 from its reverse (766171171666), we obtain a palindrome (99999999999).

The spelling of 666171171667 in words is "six hundred sixty-six billion, one hundred seventy-one million, one hundred seventy-one thousand, six hundred sixty-seven".