644216 has 8 divisors (see below), whose sum is σ = 1207920. Its totient is φ = 322104.

The previous prime is 644201. The next prime is 644227. The reversal of 644216 is 612446.

It is a happy number.

644216 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 644191 and 644200.

It is a congruent number.

It is an unprimeable number.

644216 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40256 + ... + 40271.

It is an arithmetic number, because the mean of its divisors is an integer number (150990).

2⁶⁴⁴²¹⁶ is an apocalyptic number.

It is an amenable number.

644216 is a deficient number, since it is larger than the sum of its proper divisors (563704).

644216 is a wasteful number, since it uses less digits than its factorization.

644216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80533 (or 80529 counting only the distinct ones).

The product of its digits is 1152, while the sum is 23.

The square root of 644216 is about 802.6306747191. The cubic root of 644216 is about 86.3662047755.

The spelling of 644216 in words is "six hundred forty-four thousand, two hundred sixteen".