66173271691 has 4 divisors (see below), whose sum is σ = 66224136384. Its totient is φ = 66122407000.

The previous prime is 66173271667. The next prime is 66173271701. The reversal of 66173271691 is 19617237166.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66173271691 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66173271091) 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 3 ways as a sum of consecutive naturals, for example, 25430395 + ... + 25432996.

It is an arithmetic number, because the mean of its divisors is an integer number (16556034096).

Almost surely, 2^66173271691 is an apocalyptic number.

66173271691 is a deficient number, since it is larger than the sum of its proper divisors (50864693).

66173271691 is a wasteful number, since it uses less digits than its factorization.

66173271691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50864692.

The product of its digits is 571536, while the sum is 49.

The spelling of 66173271691 in words is "sixty-six billion, one hundred seventy-three million, two hundred seventy-one thousand, six hundred ninety-one".