665131188065 has 16 divisors (see below), whose sum is σ = 842493083520. Its totient is φ = 504099400752.

The previous prime is 665131188041. The next prime is 665131188077. The reversal of 665131188065 is 560881131566.

It is not a de Polignac number, because 665131188065 - 2²⁶ = 665064079201 is a prime.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 9662909 + ... + 9731498.

It is an arithmetic number, because the mean of its divisors is an integer number (52655817720).

Almost surely, 2^665131188065 is an apocalyptic number.

It is an amenable number.

665131188065 is a deficient number, since it is larger than the sum of its proper divisors (177361895455).

665131188065 is an equidigital number, since it uses as much as digits as its factorization.

665131188065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19394469 (or 19394431 counting only the distinct ones).

The product of its (nonzero) digits is 1036800, while the sum is 50.

It can be divided in two parts, 6651311 and 88065, that added together give a palindrome (6739376).

The spelling of 665131188065 in words is "six hundred sixty-five billion, one hundred thirty-one million, one hundred eighty-eight thousand, sixty-five".