644045540447 has 8 divisors (see below), whose sum is σ = 688186818000. Its totient is φ = 600599401344.

The previous prime is 644045540407. The next prime is 644045540513. The reversal of 644045540447 is 744045540446.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644045540447 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644045540407) 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, 173782697 + ... + 173786402.

It is an arithmetic number, because the mean of its divisors is an integer number (86023352250).

Almost surely, 2^644045540447 is an apocalyptic number.

644045540447 is a deficient number, since it is larger than the sum of its proper divisors (44141277553).

644045540447 is a wasteful number, since it uses less digits than its factorization.

644045540447 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 347569225.

The product of its (nonzero) digits is 4300800, while the sum is 47.

Subtracting 644045540447 from its reverse (744045540446), we obtain a palindrome (99999999999).

The spelling of 644045540447 in words is "six hundred forty-four billion, forty-five million, five hundred forty thousand, four hundred forty-seven".