644438311630 has 16 divisors (see below), whose sum is σ = 1161159502464. Its totient is φ = 257515204320.

The previous prime is 644438311619. The next prime is 644438311661. The reversal of 644438311630 is 36113834446.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32504637 + ... + 32524456.

It is an arithmetic number, because the mean of its divisors is an integer number (72572468904).

Almost surely, 2^644438311630 is an apocalyptic number.

644438311630 is a deficient number, since it is larger than the sum of its proper divisors (516721190834).

644438311630 is a wasteful number, since it uses less digits than its factorization.

644438311630 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65030091.

The product of its (nonzero) digits is 497664, while the sum is 43.

The spelling of 644438311630 in words is "six hundred forty-four billion, four hundred thirty-eight million, three hundred eleven thousand, six hundred thirty".