644912 has 20 divisors (see below), whose sum is σ = 1323576. Its totient is φ = 303360.

The previous prime is 644911. The next prime is 644923. The reversal of 644912 is 219446.

644912 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×644912² = 831822975488, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (644911) 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, 914 + ... + 1457.

2⁶⁴⁴⁹¹² is an apocalyptic number.

It is an amenable number.

644912 is an abundant number, since it is smaller than the sum of its proper divisors (678664).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644912 is a wasteful number, since it uses less digits than its factorization.

644912 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2396 (or 2390 counting only the distinct ones).

The product of its digits is 1728, while the sum is 26.

The square root of 644912 is about 803.0641319347. The cubic root of 644912 is about 86.3972964403.

The spelling of 644912 in words is "six hundred forty-four thousand, nine hundred twelve".