66779316691 has 4 divisors (see below), whose sum is σ = 67118298192. Its totient is φ = 66440335192.

The previous prime is 66779316679. The next prime is 66779316707. The reversal of 66779316691 is 19661397766.

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 66779316691 - 2⁷ = 66779316563 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66779316601) 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, 169490455 + ... + 169490848.

It is an arithmetic number, because the mean of its divisors is an integer number (16779574548).

Almost surely, 2^66779316691 is an apocalyptic number.

66779316691 is a deficient number, since it is larger than the sum of its proper divisors (338981501).

66779316691 is a wasteful number, since it uses less digits than its factorization.

66779316691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 338981500.

The product of its digits is 15431472, while the sum is 61.

The spelling of 66779316691 in words is "sixty-six billion, seven hundred seventy-nine million, three hundred sixteen thousand, six hundred ninety-one".