644270 has 16 divisors (see below), whose sum is σ = 1265328. Its totient is φ = 234240.

The previous prime is 644261. The next prime is 644291. The reversal of 644270 is 72446.

It is a Curzon number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 644270.

It is an unprimeable number.

644270 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 7 ways as a sum of consecutive naturals, for example, 2819 + ... + 3038.

It is an arithmetic number, because the mean of its divisors is an integer number (79083).

2⁶⁴⁴²⁷⁰ is an apocalyptic number.

644270 is a deficient number, since it is larger than the sum of its proper divisors (621058).

644270 is a wasteful number, since it uses less digits than its factorization.

644270 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5875.

The product of its (nonzero) digits is 1344, while the sum is 23.

The square root of 644270 is about 802.6643133963. The cubic root of 644270 is about 86.3686178609.

It can be divided in two parts, 64 and 4270, that added together give a palindrome (4334).

The spelling of 644270 in words is "six hundred forty-four thousand, two hundred seventy".