644611265 has 8 divisors (see below), whose sum is σ = 773670528. Its totient is φ = 515597680.

The previous prime is 644611259. The next prime is 644611291. The reversal of 644611265 is 562116446.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 644611265 - 2²⁸ = 376175809 is a prime.

It is a Duffinian number.

It is a Curzon 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 7 ways as a sum of consecutive naturals, for example, 44810 + ... + 57420.

It is an arithmetic number, because the mean of its divisors is an integer number (96708816).

Almost surely, 2^644611265 is an apocalyptic number.

It is an amenable number.

644611265 is a deficient number, since it is larger than the sum of its proper divisors (129059263).

644611265 is a wasteful number, since it uses less digits than its factorization.

644611265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22839.

The product of its digits is 34560, while the sum is 35.

The square root of 644611265 is about 25389.1958320857. The cubic root of 644611265 is about 863.8386477278.

The spelling of 644611265 in words is "six hundred forty-four million, six hundred eleven thousand, two hundred sixty-five".