644617343716445 has 16 divisors (see below), whose sum is σ = 888276531055680. Its totient is φ = 444138265526400.

The previous prime is 644617343716441. The next prime is 644617343716501. The reversal of 644617343716445 is 544617343716446.

It is a happy number.

644617343716445 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 644617343716445 - 2² = 644617343716441 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644617343716441) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 308429350016 + ... + 308429352105.

It is an arithmetic number, because the mean of its divisors is an integer number (55517283190980).

Almost surely, 2^{644617343716445} is an apocalyptic number.

It is an amenable number.

644617343716445 is a deficient number, since it is larger than the sum of its proper divisors (243659187339235).

644617343716445 is a wasteful number, since it uses less digits than its factorization.

644617343716445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 616858702156.

The product of its digits is 487710720, while the sum is 65.

Subtracting from 644617343716445 its reverse (544617343716446), we obtain a palindrome (99999999999999).

The spelling of 644617343716445 in words is "six hundred forty-four trillion, six hundred seventeen billion, three hundred forty-three million, seven hundred sixteen thousand, four hundred forty-five".