644334336 has 54 divisors (see below), whose sum is σ = 1857781380. Its totient is φ = 214777344.

The previous prime is 644334331. The next prime is 644334343. The reversal of 644334336 is 633433446.

644334336 is a `hidden beast` number, since 644 + 3 + 3 + 4 + 3 + 3 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

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

It is a self number, because there is not a number n which added to its sum of digits gives 644334336.

It is not an unprimeable number, because it can be changed into a prime (644334331) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 137526 + ... + 142133.

Almost surely, 2^644334336 is an apocalyptic number.

It is an amenable number.

644334336 is an abundant number, since it is smaller than the sum of its proper divisors (1213447044).

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

644334336 is a wasteful number, since it uses less digits than its factorization.

644334336 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 279681 (or 279664 counting only the distinct ones).

The product of its digits is 186624, while the sum is 36.

The square root of 644334336 is about 25383.7415681771. The cubic root of 644334336 is about 863.7149265276.

The spelling of 644334336 in words is "six hundred forty-four million, three hundred thirty-four thousand, three hundred thirty-six".