66439657979 has 4 divisors (see below), whose sum is σ = 67186171080. Its totient is φ = 65693144880.

The previous prime is 66439657967. The next prime is 66439657987. The reversal of 66439657979 is 97975693466.

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-66439657979 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66439657909) 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, 373256417 + ... + 373256594.

It is an arithmetic number, because the mean of its divisors is an integer number (16796542770).

Almost surely, 2^66439657979 is an apocalyptic number.

66439657979 is a deficient number, since it is larger than the sum of its proper divisors (746513101).

66439657979 is an equidigital number, since it uses as much as digits as its factorization.

66439657979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 746513100.

The product of its digits is 462944160, while the sum is 71.

The spelling of 66439657979 in words is "sixty-six billion, four hundred thirty-nine million, six hundred fifty-seven thousand, nine hundred seventy-nine".