644512 has 24 divisors (see below), whose sum is σ = 1384992. Its totient is φ = 292800.

The previous prime is 644507. The next prime is 644513. The reversal of 644512 is 215446.

It is a Harshad number since it is a multiple of its sum of digits (22).

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, 564 + ... + 1267.

It is an arithmetic number, because the mean of its divisors is an integer number (57708).

2⁶⁴⁴⁵¹² is an apocalyptic number.

It is an amenable number.

644512 is an abundant number, since it is smaller than the sum of its proper divisors (740480).

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

644512 is a wasteful number, since it uses less digits than its factorization.

644512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1852 (or 1844 counting only the distinct ones).

The product of its digits is 960, while the sum is 22.

The square root of 644512 is about 802.8150471933. The cubic root of 644512 is about 86.3794304028.

Adding to 644512 its reverse (215446), we get a palindrome (859958).

It can be divided in two parts, 644 and 512, that added together give a square (1156 = 34²).

The spelling of 644512 in words is "six hundred forty-four thousand, five hundred twelve".