644821324 has 24 divisors (see below), whose sum is σ = 1290184448. Its totient is φ = 276235920.

The previous prime is 644821321. The next prime is 644821327. The reversal of 644821324 is 423128446.

644821324 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (644821321) and next prime (644821327).

It is a super-2 number, since 2×644821324² = 831589079770225952, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 644821324.

It is not an unprimeable number, because it can be changed into a prime (644821321) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 115747 + ... + 121189.

Almost surely, 2^644821324 is an apocalyptic number.

It is an amenable number.

644821324 is an abundant number, since it is smaller than the sum of its proper divisors (645363124).

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

644821324 is a wasteful number, since it uses less digits than its factorization.

644821324 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9685 (or 9683 counting only the distinct ones).

The product of its digits is 36864, while the sum is 34.

The square root of 644821324 is about 25393.3322744377. The cubic root of 644821324 is about 863.9324703594.

It can be divided in two parts, 6448 and 21324, that added together give a palindrome (27772).

The spelling of 644821324 in words is "six hundred forty-four million, eight hundred twenty-one thousand, three hundred twenty-four".