644446 has 12 divisors (see below), whose sum is σ = 1062936. Its totient is φ = 292820.

The previous prime is 644443. The next prime is 644447.

644446 is nontrivially palindromic in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644443) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1090 + ... + 1573.

It is an arithmetic number, because the mean of its divisors is an integer number (88578).

2⁶⁴⁴⁴⁴⁶ is an apocalyptic number.

644446 is a deficient number, since it is larger than the sum of its proper divisors (418490).

644446 is a wasteful number, since it uses less digits than its factorization.

644446 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2687 (or 2676 counting only the distinct ones).

The product of its digits is 9216, while the sum is 28.

The square root of 644446 is about 802.7739407828. The cubic root of 644446 is about 86.3764817962.

The spelling of 644446 in words is "six hundred forty-four thousand, four hundred forty-six".