66912784679 has 4 divisors (see below), whose sum is σ = 72059921976. Its totient is φ = 61765647384.

The previous prime is 66912784667. The next prime is 66912784691. The reversal of 66912784679 is 97648721966.

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

It is an interprime number because it is at equal distance from previous prime (66912784667) and next prime (66912784691).

It is a cyclic number.

It is not a de Polignac number, because 66912784679 - 2²⁰ = 66911736103 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66912787679) 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, 2573568629 + ... + 2573568654.

It is an arithmetic number, because the mean of its divisors is an integer number (18014980494).

Almost surely, 2^66912784679 is an apocalyptic number.

66912784679 is a deficient number, since it is larger than the sum of its proper divisors (5147137297).

66912784679 is a wasteful number, since it uses less digits than its factorization.

66912784679 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5147137296.

The product of its digits is 54867456, while the sum is 65.

The spelling of 66912784679 in words is "sixty-six billion, nine hundred twelve million, seven hundred eighty-four thousand, six hundred seventy-nine".