644441 has 8 divisors (see below), whose sum is σ = 753984. Its totient is φ = 539280.

The previous prime is 644431. The next prime is 644443. The reversal of 644441 is 144446.

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

It is not a de Polignac number, because 644441 - 2⁶ = 644377 is a prime.

It is a nialpdrome in base 10.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 644441.

It is not an unprimeable number, because it can be changed into a prime (644443) 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, 770 + ... + 1371.

It is an arithmetic number, because the mean of its divisors is an integer number (94248).

2⁶⁴⁴⁴⁴¹ is an apocalyptic number.

It is an amenable number.

644441 is a deficient number, since it is larger than the sum of its proper divisors (109543).

644441 is a wasteful number, since it uses less digits than its factorization.

644441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2191.

The product of its digits is 1536, while the sum is 23.

The square root of 644441 is about 802.7708265751. The cubic root of 644441 is about 86.3762584087.

Adding to 644441 its reverse (144446), we get a palindrome (788887).

The spelling of 644441 in words is "six hundred forty-four thousand, four hundred forty-one".