644306 has 8 divisors (see below), whose sum is σ = 1040844. Its totient is φ = 297360.

The previous prime is 644297. The next prime is 644327. The reversal of 644306 is 603446.

644306 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 2 ways, for example, as 600625 + 43681 = 775^2 + 209^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12365 + ... + 12416.

2⁶⁴⁴³⁰⁶ is an apocalyptic number.

644306 is a deficient number, since it is larger than the sum of its proper divisors (396538).

644306 is a wasteful number, since it uses less digits than its factorization.

644306 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24796.

The product of its (nonzero) digits is 1728, while the sum is 23.

The square root of 644306 is about 802.6867383980. The cubic root of 644306 is about 86.3702265096.

The spelling of 644306 in words is "six hundred forty-four thousand, three hundred six".