644749574709 has 8 divisors (see below), whose sum is σ = 859845702240. Its totient is φ = 429743248496.

The previous prime is 644749574671. The next prime is 644749574743. The reversal of 644749574709 is 907475947446.

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 644749574709 - 2²⁰ = 644748526133 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 644749574709.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644749574509) by changing a digit.

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, 22433574 + ... + 22462295.

It is an arithmetic number, because the mean of its divisors is an integer number (107480712780).

Almost surely, 2^644749574709 is an apocalyptic number.

It is an amenable number.

644749574709 is a deficient number, since it is larger than the sum of its proper divisors (215096127531).

644749574709 is a wasteful number, since it uses less digits than its factorization.

644749574709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44900659.

The product of its (nonzero) digits is 213373440, while the sum is 66.

The spelling of 644749574709 in words is "six hundred forty-four billion, seven hundred forty-nine million, five hundred seventy-four thousand, seven hundred nine".