66185138879 has 4 divisors (see below), whose sum is σ = 66316720176. Its totient is φ = 66053557584.

The previous prime is 66185138863. The next prime is 66185138893. The reversal of 66185138879 is 97883158166.

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 66185138879 - 2⁴ = 66185138863 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 (66185138819) 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, 65789894 + ... + 65790899.

It is an arithmetic number, because the mean of its divisors is an integer number (16579180044).

Almost surely, 2^66185138879 is an apocalyptic number.

66185138879 is a deficient number, since it is larger than the sum of its proper divisors (131581297).

66185138879 is a wasteful number, since it uses less digits than its factorization.

66185138879 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131581296.

The product of its digits is 17418240, while the sum is 62.

The spelling of 66185138879 in words is "sixty-six billion, one hundred eighty-five million, one hundred thirty-eight thousand, eight hundred seventy-nine".