644612 has 12 divisors (see below), whose sum is σ = 1167180. Its totient is φ = 311136.

The previous prime is 644599. The next prime is 644617. The reversal of 644612 is 216446.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 495616 + 148996 = 704^2 + 386^2 .

It is not an unprimeable number, because it can be changed into a prime (644617) by changing a digit.

644612 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 in 3 ways as a sum of consecutive naturals, for example, 2663 + ... + 2894.

It is an arithmetic number, because the mean of its divisors is an integer number (97265).

2⁶⁴⁴⁶¹² is an apocalyptic number.

It is an amenable number.

644612 is a deficient number, since it is larger than the sum of its proper divisors (522568).

644612 is a wasteful number, since it uses less digits than its factorization.

644612 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5590 (or 5588 counting only the distinct ones).

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

The square root of 644612 is about 802.8773256233. The cubic root of 644612 is about 86.3838976050.

The spelling of 644612 in words is "six hundred forty-four thousand, six hundred twelve".