644361376 has 24 divisors (see below), whose sum is σ = 1323743904. Its totient is φ = 308172480.

The previous prime is 644361323. The next prime is 644361391. The reversal of 644361376 is 673163446.

It is a happy number.

It is a super-2 number, since 2×644361376² = 830403165761226752, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 437010 + ... + 438481.

It is an arithmetic number, because the mean of its divisors is an integer number (55155996).

Almost surely, 2^644361376 is an apocalyptic number.

It is an amenable number.

644361376 is an abundant number, since it is smaller than the sum of its proper divisors (679382528).

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

644361376 is a wasteful number, since it uses less digits than its factorization.

644361376 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 875524 (or 875516 counting only the distinct ones).

The product of its digits is 217728, while the sum is 40.

The square root of 644361376 is about 25384.2741869844. The cubic root of 644361376 is about 863.7270085186.

The spelling of 644361376 in words is "six hundred forty-four million, three hundred sixty-one thousand, three hundred seventy-six".