64645565 has 4 divisors (see below), whose sum is σ = 77574684. Its totient is φ = 51716448.

The previous prime is 64645517. The next prime is 64645573. The reversal of 64645565 is 56554646.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56554646 = 2 ⋅28277323.

It can be written as a sum of positive squares in 2 ways, for example, as 14830201 + 49815364 = 3851^2 + 7058^2 .

It is a cyclic number.

It is not a de Polignac number, because 64645565 - 2¹⁴ = 64629181 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 6464552 + ... + 6464561.

It is an arithmetic number, because the mean of its divisors is an integer number (19393671).

Almost surely, 2^64645565 is an apocalyptic number.

It is an amenable number.

64645565 is a deficient number, since it is larger than the sum of its proper divisors (12929119).

64645565 is a wasteful number, since it uses less digits than its factorization.

64645565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12929118.

The product of its digits is 432000, while the sum is 41.

The square root of 64645565 is about 8040.2465758209. The cubic root of 64645565 is about 401.3404301831.

The spelling of 64645565 in words is "sixty-four million, six hundred forty-five thousand, five hundred sixty-five".