644846 has 8 divisors (see below), whose sum is σ = 970704. Its totient is φ = 321280.

The previous prime is 644843. The next prime is 644857. The reversal of 644846 is 648446.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644843) 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 3 ways as a sum of consecutive naturals, for example, 686 + ... + 1326.

It is an arithmetic number, because the mean of its divisors is an integer number (121338).

2⁶⁴⁴⁸⁴⁶ is an apocalyptic number.

644846 is a deficient number, since it is larger than the sum of its proper divisors (325858).

644846 is a wasteful number, since it uses less digits than its factorization.

644846 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1146.

The product of its digits is 18432, while the sum is 32.

The square root of 644846 is about 803.0230382747. The cubic root of 644846 is about 86.3943490531.

Subtracting 644846 from its reverse (648446), we obtain a square (3600 = 60²).

The spelling of 644846 in words is "six hundred forty-four thousand, eight hundred forty-six".