644322312 has 24 divisors (see below), whose sum is σ = 1745039790. Its totient is φ = 214774080.

The previous prime is 644322307. The next prime is 644322331. The reversal of 644322312 is 213223446.

644322312 is a `hidden beast` number, since 644 + 3 + 2 + 2 + 3 + 12 = 666.

It can be written as a sum of positive squares in only one way, i.e., 596629476 + 47692836 = 24426^2 + 6906^2 .

It is a tau number, because it is divible by the number of its divisors (24).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4474389 + ... + 4474532.

Almost surely, 2^644322312 is an apocalyptic number.

It is an amenable number.

644322312 is an abundant number, since it is smaller than the sum of its proper divisors (1100717478).

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

644322312 is a wasteful number, since it uses less digits than its factorization.

644322312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8948933 (or 8948926 counting only the distinct ones).

The product of its digits is 6912, while the sum is 27.

The square root of 644322312 is about 25383.5047225556. The cubic root of 644322312 is about 863.7095538650.

Adding to 644322312 its reverse (213223446), we get a palindrome (857545758).

The spelling of 644322312 in words is "six hundred forty-four million, three hundred twenty-two thousand, three hundred twelve".