644244442445 has 8 divisors (see below), whose sum is σ = 773098110720. Its totient is φ = 515392367440.

The previous prime is 644244442441. The next prime is 644244442531. The reversal of 644244442445 is 544244442446.

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

It is not a de Polignac number, because 644244442445 - 2² = 644244442441 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 644244442445.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644244442441) 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, 842876 + ... + 1413834.

It is an arithmetic number, because the mean of its divisors is an integer number (96637263840).

Almost surely, 2^644244442445 is an apocalyptic number.

It is an amenable number.

644244442445 is a deficient number, since it is larger than the sum of its proper divisors (128853668275).

644244442445 is a wasteful number, since it uses less digits than its factorization.

644244442445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 796635.

The product of its digits is 7864320, while the sum is 47.

Subtracting from 644244442445 its reverse (544244442446), we obtain a palindrome (99999999999).

The spelling of 644244442445 in words is "six hundred forty-four billion, two hundred forty-four million, four hundred forty-two thousand, four hundred forty-five".