644265 has 24 divisors (see below), whose sum is σ = 1135680. Its totient is φ = 337824.

The previous prime is 644261. The next prime is 644291. The reversal of 644265 is 562446.

It is a happy number.

644265 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 644265 - 2² = 644261 is a prime.

It is a d-powerful number, because it can be written as 6⁵ + 4 + 2¹⁹ + 4⁸ + 6⁶ + 5 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (644261) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4566 + ... + 4704.

It is an arithmetic number, because the mean of its divisors is an integer number (47320).

2⁶⁴⁴²⁶⁵ is an apocalyptic number.

It is an amenable number.

644265 is a deficient number, since it is larger than the sum of its proper divisors (491415).

644265 is a wasteful number, since it uses less digits than its factorization.

644265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 253 (or 250 counting only the distinct ones).

The product of its digits is 5760, while the sum is 27.

The square root of 644265 is about 802.6611987632. The cubic root of 644265 is about 86.3683944327.

It can be divided in two parts, 644 and 265, that added together give a palindrome (909).

The spelling of 644265 in words is "six hundred forty-four thousand, two hundred sixty-five".