644144 has 20 divisors (see below), whose sum is σ = 1261824. Its totient is φ = 318528.

The previous prime is 644143. The next prime is 644153. The reversal of 644144 is 441446.

It is a hoax number, since the sum of its digits (23) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (644141) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1874 + ... + 2190.

2⁶⁴⁴¹⁴⁴ is an apocalyptic number.

It is an amenable number.

644144 is a deficient number, since it is larger than the sum of its proper divisors (617680).

644144 is a wasteful number, since it uses less digits than its factorization.

644144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 452 (or 446 counting only the distinct ones).

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

The square root of 644144 is about 802.5858209562. The cubic root of 644144 is about 86.3629871184.

The spelling of 644144 in words is "six hundred forty-four thousand, one hundred forty-four".