644361424 has 80 divisors (see below), whose sum is σ = 1457049600. Its totient is φ = 270369792.

The previous prime is 644361413. The next prime is 644361461. The reversal of 644361424 is 424163446.

It is a self number, because there is not a number n which added to its sum of digits gives 644361424.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1265682 + ... + 1266190.

It is an arithmetic number, because the mean of its divisors is an integer number (18213120).

Almost surely, 2^644361424 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644361424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (728524800).

644361424 is an abundant number, since it is smaller than the sum of its proper divisors (812688176).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644361424 is a wasteful number, since it uses less digits than its factorization.

644361424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 740 (or 734 counting only the distinct ones).

The product of its digits is 55296, while the sum is 34.

The square root of 644361424 is about 25384.2751324516. The cubic root of 644361424 is about 863.7270299656.

The spelling of 644361424 in words is "six hundred forty-four million, three hundred sixty-one thousand, four hundred twenty-four".