644830016 has 14 divisors (see below), whose sum is σ = 1279584690. Its totient is φ = 322414976.

The previous prime is 644830013. The next prime is 644830019. The reversal of 644830016 is 610038446.

It is an interprime number because it is at equal distance from previous prime (644830013) and next prime (644830019).

It can be written as a sum of positive squares in only one way, i.e., 643129600 + 1700416 = 25360^2 + 1304^2 .

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644830013) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5037671 + ... + 5037798.

Almost surely, 2^644830016 is an apocalyptic number.

It is an amenable number.

644830016 is a deficient number, since it is larger than the sum of its proper divisors (634754674).

644830016 is a wasteful number, since it uses less digits than its factorization.

644830016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10075481 (or 10075471 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 32.

The square root of 644830016 is about 25393.5034211509. The cubic root of 644830016 is about 863.9363521930.

The spelling of 644830016 in words is "six hundred forty-four million, eight hundred thirty thousand, sixteen".