644327764 has 12 divisors (see below), whose sum is σ = 1128265684. Its totient is φ = 321966144.

The previous prime is 644327743. The next prime is 644327779. The reversal of 644327764 is 467723446.

644327764 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 232562500 + 411765264 = 15250^2 + 20292^2 .

It is a super-2 number, since 2×644327764² = 830316534922479392, which contains 22 as substring.

It is a hoax number, since the sum of its digits (43) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 644327764.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41979 + ... + 55234.

Almost surely, 2^644327764 is an apocalyptic number.

It is an amenable number.

644327764 is a deficient number, since it is larger than the sum of its proper divisors (483937920).

644327764 is a wasteful number, since it uses less digits than its factorization.

644327764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98874 (or 98872 counting only the distinct ones).

The product of its digits is 677376, while the sum is 43.

The square root of 644327764 is about 25383.6121149059. The cubic root of 644327764 is about 863.7119899808.

The spelling of 644327764 in words is "six hundred forty-four million, three hundred twenty-seven thousand, seven hundred sixty-four".