644307 has 8 divisors (see below), whose sum is σ = 863184. Its totient is φ = 427488.

The previous prime is 644297. The next prime is 644327. The reversal of 644307 is 703446.

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

It is not a de Polignac number, because 644307 - 2⁴ = 644291 is a prime.

It is not an unprimeable number, because it can be changed into a prime (644327) by changing a digit.

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, 513 + ... + 1245.

It is an arithmetic number, because the mean of its divisors is an integer number (107898).

2⁶⁴⁴³⁰⁷ is an apocalyptic number.

644307 is a deficient number, since it is larger than the sum of its proper divisors (218877).

644307 is a wasteful number, since it uses less digits than its factorization.

644307 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1029.

The product of its (nonzero) digits is 2016, while the sum is 24.

The square root of 644307 is about 802.6873613058. The cubic root of 644307 is about 86.3702711935.

It can be divided in two parts, 64 and 4307, that added together give a triangular number (4371 = T₉₃).

The spelling of 644307 in words is "six hundred forty-four thousand, three hundred seven".