644707 has 8 divisors (see below), whose sum is σ = 760832. Its totient is φ = 534600.

The previous prime is 644701. The next prime is 644717. The reversal of 644707 is 707446.

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

It is a cyclic number.

It is not a de Polignac number, because 644707 - 2¹⁵ = 611939 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644701) 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, 1269 + ... + 1702.

It is an arithmetic number, because the mean of its divisors is an integer number (95104).

2⁶⁴⁴⁷⁰⁷ is an apocalyptic number.

644707 is a deficient number, since it is larger than the sum of its proper divisors (116125).

644707 is a wasteful number, since it uses less digits than its factorization.

644707 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3009.

The product of its (nonzero) digits is 4704, while the sum is 28.

The square root of 644707 is about 802.9364856575. The cubic root of 644707 is about 86.3881410192.

The spelling of 644707 in words is "six hundred forty-four thousand, seven hundred seven".