665447216667 has 16 divisors (see below), whose sum is σ = 896239868160. Its totient is φ = 439146509472.

The previous prime is 665447216587. The next prime is 665447216671. The reversal of 665447216667 is 766612744566.

It is not a de Polignac number, because 665447216667 - 2²³ = 665438828059 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 665447216667.

It is not an unprimeable number, because it can be changed into a prime (665447266667) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 330684 + ... + 1200102.

It is an arithmetic number, because the mean of its divisors is an integer number (56014991760).

Almost surely, 2^665447216667 is an apocalyptic number.

665447216667 is a deficient number, since it is larger than the sum of its proper divisors (230792651493).

665447216667 is a wasteful number, since it uses less digits than its factorization.

665447216667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 872002.

The product of its digits is 60963840, while the sum is 60.

The spelling of 665447216667 in words is "six hundred sixty-five billion, four hundred forty-seven million, two hundred sixteen thousand, six hundred sixty-seven".