644263362445 has 8 divisors (see below), whose sum is σ = 774455927544. Its totient is φ = 514517428224.

The previous prime is 644263362401. The next prime is 644263362527. The reversal of 644263362445 is 544263362446.

It can be written as a sum of positive squares in 4 ways, for example, as 114050745796 + 530212616649 = 337714^2 + 728157^2 .

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 644263362445 - 2¹⁹ = 644262838157 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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, 111654544 + ... + 111660313.

It is an arithmetic number, because the mean of its divisors is an integer number (96806990943).

Almost surely, 2^644263362445 is an apocalyptic number.

It is an amenable number.

644263362445 is a deficient number, since it is larger than the sum of its proper divisors (130192565099).

644263362445 is a wasteful number, since it uses less digits than its factorization.

644263362445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223315439.

The product of its digits is 9953280, while the sum is 49.

Subtracting from 644263362445 its reverse (544263362446), we obtain a palindrome (99999999999).

The spelling of 644263362445 in words is "six hundred forty-four billion, two hundred sixty-three million, three hundred sixty-two thousand, four hundred forty-five".