644235065 has 16 divisors (see below), whose sum is σ = 785514240. Its totient is φ = 507163200.

The previous prime is 644235049. The next prime is 644235079. The reversal of 644235065 is 560532446.

It is a happy number.

It is not a de Polignac number, because 644235065 - 2⁴ = 644235049 is a prime.

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 15 ways as a sum of consecutive naturals, for example, 80516 + ... + 88154.

It is an arithmetic number, because the mean of its divisors is an integer number (49094640).

Almost surely, 2^644235065 is an apocalyptic number.

It is an amenable number.

644235065 is a deficient number, since it is larger than the sum of its proper divisors (141279175).

644235065 is a wasteful number, since it uses less digits than its factorization.

644235065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7912.

The product of its (nonzero) digits is 86400, while the sum is 35.

The square root of 644235065 is about 25381.7860876653. The cubic root of 644235065 is about 863.6705674408.

The spelling of 644235065 in words is "six hundred forty-four million, two hundred thirty-five thousand, sixty-five".