644516 has 12 divisors (see below), whose sum is σ = 1147440. Its totient is φ = 316680.

The previous prime is 644513. The next prime is 644519. The reversal of 644516 is 615446.

It is a happy number.

644516 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (644513) and next prime (644519).

It is not an unprimeable number, because it can be changed into a prime (644513) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1130 + ... + 1601.

It is an arithmetic number, because the mean of its divisors is an integer number (95620).

2⁶⁴⁴⁵¹⁶ is an apocalyptic number.

It is an amenable number.

644516 is a deficient number, since it is larger than the sum of its proper divisors (502924).

644516 is a wasteful number, since it uses less digits than its factorization.

644516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2794 (or 2792 counting only the distinct ones).

The product of its digits is 2880, while the sum is 26.

The square root of 644516 is about 802.8175384233. The cubic root of 644516 is about 86.3796090998.

The spelling of 644516 in words is "six hundred forty-four thousand, five hundred sixteen".