644020617 has 8 divisors (see below), whose sum is σ = 859921920. Its totient is φ = 428733200.

The previous prime is 644020607. The next prime is 644020651. The reversal of 644020617 is 716020446.

644020617 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 644020617 - 2⁸ = 644020361 is a prime.

It is not an unprimeable number, because it can be changed into a prime (644020607) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 151017 + ... + 155222.

It is an arithmetic number, because the mean of its divisors is an integer number (107490240).

Almost surely, 2^644020617 is an apocalyptic number.

It is an amenable number.

644020617 is a deficient number, since it is larger than the sum of its proper divisors (215901303).

644020617 is a wasteful number, since it uses less digits than its factorization.

644020617 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 306943.

The product of its (nonzero) digits is 8064, while the sum is 30.

The square root of 644020617 is about 25377.5612894541. The cubic root of 644020617 is about 863.5747261398.

The spelling of 644020617 in words is "six hundred forty-four million, twenty thousand, six hundred seventeen".