66871710891 has 8 divisors (see below), whose sum is σ = 99069201360. Its totient is φ = 44581140576.

The previous prime is 66871710839. The next prime is 66871710923. The reversal of 66871710891 is 19801717866.

It is not a de Polignac number, because 66871710891 - 2⁹ = 66871710379 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66871710821) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1238364990 + ... + 1238365043.

It is an arithmetic number, because the mean of its divisors is an integer number (12383650170).

Almost surely, 2^66871710891 is an apocalyptic number.

66871710891 is a deficient number, since it is larger than the sum of its proper divisors (32197490469).

66871710891 is a wasteful number, since it uses less digits than its factorization.

66871710891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2476730042 (or 2476730036 counting only the distinct ones).

The product of its (nonzero) digits is 1016064, while the sum is 54.

The spelling of 66871710891 in words is "sixty-six billion, eight hundred seventy-one million, seven hundred ten thousand, eight hundred ninety-one".