665165641 has 12 divisors (see below), whose sum is σ = 774385812. Its totient is φ = 569683968.

The previous prime is 665165621. The next prime is 665165653. The reversal of 665165641 is 146561566.

It can be written as a sum of positive squares in 2 ways, for example, as 608855625 + 56310016 = 24675^2 + 7504^2 .

It is not a de Polignac number, because 665165641 - 2⁵ = 665165609 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 665165594 and 665165603.

It is not an unprimeable number, because it can be changed into a prime (665165621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 65481 + ... + 74953.

It is an arithmetic number, because the mean of its divisors is an integer number (64532151).

Almost surely, 2^665165641 is an apocalyptic number.

It is an amenable number.

665165641 is a deficient number, since it is larger than the sum of its proper divisors (109220171).

665165641 is a wasteful number, since it uses less digits than its factorization.

665165641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10920 (or 10913 counting only the distinct ones).

The product of its digits is 129600, while the sum is 40.

The square root of 665165641 is about 25790.8053577239. The cubic root of 665165641 is about 872.9243387089.

The spelling of 665165641 in words is "six hundred sixty-five million, one hundred sixty-five thousand, six hundred forty-one".