665221052065 has 16 divisors (see below), whose sum is σ = 839563232256. Its totient is φ = 505292673600.

The previous prime is 665221052063. The next prime is 665221052107. The reversal of 665221052065 is 560250122566.

It is not a de Polignac number, because 665221052065 - 2¹ = 665221052063 is a prime.

It is a super-2 number, since 2×665221052065² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665221052063) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 40479981 + ... + 40496410.

It is an arithmetic number, because the mean of its divisors is an integer number (52472702016).

Almost surely, 2^665221052065 is an apocalyptic number.

It is an amenable number.

665221052065 is a deficient number, since it is larger than the sum of its proper divisors (174342180191).

665221052065 is a wasteful number, since it uses less digits than its factorization.

665221052065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80976480.

The product of its (nonzero) digits is 216000, while the sum is 40.

The spelling of 665221052065 in words is "six hundred sixty-five billion, two hundred twenty-one million, fifty-two thousand, sixty-five".