644716 has 12 divisors (see below), whose sum is σ = 1141560. Its totient is φ = 318560.

The previous prime is 644701. The next prime is 644717. The reversal of 644716 is 617446.

It is not an unprimeable number, because it can be changed into a prime (644717) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 550 + ... + 1261.

It is an arithmetic number, because the mean of its divisors is an integer number (95130).

2⁶⁴⁴⁷¹⁶ is an apocalyptic number.

It is an amenable number.

644716 is a deficient number, since it is larger than the sum of its proper divisors (496844).

644716 is a wasteful number, since it uses less digits than its factorization.

644716 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1904 (or 1902 counting only the distinct ones).

The product of its digits is 4032, while the sum is 28.

The square root of 644716 is about 802.9420900663. The cubic root of 644716 is about 86.3885430053.

The spelling of 644716 in words is "six hundred forty-four thousand, seven hundred sixteen".