644469808 has 10 divisors (see below), whose sum is σ = 1248660284. Its totient is φ = 322234896.

The previous prime is 644469751. The next prime is 644469809. The reversal of 644469808 is 808964446.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (644469809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20139666 + ... + 20139697.

Almost surely, 2^644469808 is an apocalyptic number.

It is an amenable number.

644469808 is a deficient number, since it is larger than the sum of its proper divisors (604190476).

644469808 is a wasteful number, since it uses less digits than its factorization.

644469808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40279371 (or 40279365 counting only the distinct ones).

The product of its (nonzero) digits is 1327104, while the sum is 49.

The square root of 644469808 is about 25386.4099076652. The cubic root of 644469808 is about 863.7754546222.

The spelling of 644469808 in words is "six hundred forty-four million, four hundred sixty-nine thousand, eight hundred eight".