665126078767 has 4 divisors (see below), whose sum is σ = 681348666096. Its totient is φ = 648903491440.

The previous prime is 665126078719. The next prime is 665126078779. The reversal of 665126078767 is 767870621566.

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-665126078767 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 (665126078707) 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, 8111293603 + ... + 8111293684.

It is an arithmetic number, because the mean of its divisors is an integer number (170337166524).

Almost surely, 2^665126078767 is an apocalyptic number.

665126078767 is a deficient number, since it is larger than the sum of its proper divisors (16222587329).

665126078767 is a wasteful number, since it uses less digits than its factorization.

665126078767 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16222587328.

The product of its (nonzero) digits is 35562240, while the sum is 61.

The spelling of 665126078767 in words is "six hundred sixty-five billion, one hundred twenty-six million, seventy-eight thousand, seven hundred sixty-seven".