64666565 has 16 divisors (see below), whose sum is σ = 80036208. Its totient is φ = 50121216.

The previous prime is 64666561. The next prime is 64666577. The reversal of 64666565 is 56566646.

It can be written as a sum of positive squares in 8 ways, for example, as 11682724 + 52983841 = 3418^2 + 7279^2 .

It is a cyclic number.

It is not a de Polignac number, because 64666565 - 2² = 64666561 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 (64666561) 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 15 ways as a sum of consecutive naturals, for example, 53609 + ... + 54801.

It is an arithmetic number, because the mean of its divisors is an integer number (5002263).

Almost surely, 2^64666565 is an apocalyptic number.

It is an amenable number.

64666565 is a deficient number, since it is larger than the sum of its proper divisors (15369643).

64666565 is a wasteful number, since it uses less digits than its factorization.

64666565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1528.

The product of its digits is 777600, while the sum is 44.

The square root of 64666565 is about 8041.5523998790. The cubic root of 64666565 is about 401.3838837264.

It can be divided in two parts, 6466 and 6565, that added together give a palindrome (13031).

The spelling of 64666565 in words is "sixty-four million, six hundred sixty-six thousand, five hundred sixty-five".