644727 has 8 divisors (see below), whose sum is σ = 904960. Its totient is φ = 407160.

The previous prime is 644717. The next prime is 644729. The reversal of 644727 is 727446.

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

It is not a de Polignac number, because 644727 - 2⁷ = 644599 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 644694 and 644703.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 644727.

It is not an unprimeable number, because it can be changed into a prime (644729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5599 + ... + 5712.

It is an arithmetic number, because the mean of its divisors is an integer number (113120).

2⁶⁴⁴⁷²⁷ is an apocalyptic number.

644727 is a deficient number, since it is larger than the sum of its proper divisors (260233).

644727 is a wasteful number, since it uses less digits than its factorization.

644727 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11333.

The product of its digits is 9408, while the sum is 30.

The square root of 644727 is about 802.9489398461. The cubic root of 644727 is about 86.3890343165.

The spelling of 644727 in words is "six hundred forty-four thousand, seven hundred twenty-seven".