79566666665 has 4 divisors (see below), whose sum is σ = 95480000004. Its totient is φ = 63653333328.

The previous prime is 79566666653. The next prime is 79566666701. The reversal of 79566666665 is 56666666597.

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

It can be written as a sum of positive squares in 2 ways, for example, as 56826931456 + 22739735209 = 238384^2 + 150797^2 .

It is a cyclic number.

It is not a de Polignac number, because 79566666665 - 2²⁰ = 79565618089 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 79566666595 and 79566666604.

It is an unprimeable number.

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, 7956666662 + ... + 7956666671.

It is an arithmetic number, because the mean of its divisors is an integer number (23870000001).

Almost surely, 2^79566666665 is an apocalyptic number.

It is an amenable number.

79566666665 is a deficient number, since it is larger than the sum of its proper divisors (15913333339).

79566666665 is a wasteful number, since it uses less digits than its factorization.

79566666665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15913333338.

The product of its digits is 440899200, while the sum is 68.

Subtracting from 79566666665 its sum of digits (68), we obtain a palindrome (79566666597).

The spelling of 79566666665 in words is "seventy-nine billion, five hundred sixty-six million, six hundred sixty-six thousand, six hundred sixty-five".