644318281617 has 8 divisors (see below), whose sum is σ = 860946532224. Its totient is φ = 428617776048.

The previous prime is 644318281583. The next prime is 644318281643. The reversal of 644318281617 is 716182813446.

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

It is not a de Polignac number, because 644318281617 - 2⁶ = 644318281553 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 644318281617.

It is not an unprimeable number, because it can be changed into a prime (644318283617) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 231934638 + ... + 231937415.

It is an arithmetic number, because the mean of its divisors is an integer number (107618316528).

Almost surely, 2^644318281617 is an apocalyptic number.

It is an amenable number.

644318281617 is a deficient number, since it is larger than the sum of its proper divisors (216628250607).

644318281617 is a wasteful number, since it uses less digits than its factorization.

644318281617 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 463872519.

The product of its digits is 1548288, while the sum is 51.

The spelling of 644318281617 in words is "six hundred forty-four billion, three hundred eighteen million, two hundred eighty-one thousand, six hundred seventeen".