644535814 has 16 divisors (see below), whose sum is σ = 1042795152. Its totient is φ = 297014688.

The previous prime is 644535797. The next prime is 644535823. The reversal of 644535814 is 418535446.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2004 + ... + 35959.

It is an arithmetic number, because the mean of its divisors is an integer number (65174697).

Almost surely, 2^644535814 is an apocalyptic number.

644535814 is a deficient number, since it is larger than the sum of its proper divisors (398259338).

644535814 is a wasteful number, since it uses less digits than its factorization.

644535814 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38631.

The product of its digits is 230400, while the sum is 40.

The square root of 644535814 is about 25387.7099006586. The cubic root of 644535814 is about 863.8049426425.

The spelling of 644535814 in words is "six hundred forty-four million, five hundred thirty-five thousand, eight hundred fourteen".