644373 has 6 divisors (see below), whose sum is σ = 930774. Its totient is φ = 429576.

The previous prime is 644363. The next prime is 644377. The reversal of 644373 is 373446.

644373 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 636804 + 7569 = 798^2 + 87^2 .

It is not a de Polignac number, because 644373 - 2⁵ = 644341 is a prime.

It is a d-powerful number, because it can be written as 6⁶ + 4 + 3⁶ + 4⁸ + 7 + 3¹² .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644377) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 35790 + ... + 35807.

It is an arithmetic number, because the mean of its divisors is an integer number (155129).

2⁶⁴⁴³⁷³ is an apocalyptic number.

It is an amenable number.

644373 is a deficient number, since it is larger than the sum of its proper divisors (286401).

644373 is a wasteful number, since it uses less digits than its factorization.

644373 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71603 (or 71600 counting only the distinct ones).

The product of its digits is 6048, while the sum is 27.

The square root of 644373 is about 802.7284721498. The cubic root of 644373 is about 86.3732202241.

The spelling of 644373 in words is "six hundred forty-four thousand, three hundred seventy-three".