644431226713 has 4 divisors (see below), whose sum is σ = 644652759780. Its totient is φ = 644209693648.

The previous prime is 644431226693. The next prime is 644431226809. The reversal of 644431226713 is 317622134446.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 568769372224 + 75661854489 = 754168^2 + 275067^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644431226713 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 644431226713.

It is not an unprimeable number, because it can be changed into a prime (644431226113) 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 3 ways as a sum of consecutive naturals, for example, 110762170 + ... + 110767987.

It is an arithmetic number, because the mean of its divisors is an integer number (161163189945).

Almost surely, 2^644431226713 is an apocalyptic number.

It is an amenable number.

644431226713 is a deficient number, since it is larger than the sum of its proper divisors (221533067).

644431226713 is a wasteful number, since it uses less digits than its factorization.

644431226713 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221533066.

The product of its digits is 580608, while the sum is 43.

The spelling of 644431226713 in words is "six hundred forty-four billion, four hundred thirty-one million, two hundred twenty-six thousand, seven hundred thirteen".