644043 has 8 divisors (see below), whose sum is σ = 904000. Its totient is φ = 406728.

The previous prime is 644029. The next prime is 644047. The reversal of 644043 is 340446.

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

It is not a de Polignac number, because 644043 - 2¹⁴ = 627659 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644047) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5593 + ... + 5706.

It is an arithmetic number, because the mean of its divisors is an integer number (113000).

2⁶⁴⁴⁰⁴³ is an apocalyptic number.

644043 is a deficient number, since it is larger than the sum of its proper divisors (259957).

644043 is a wasteful number, since it uses less digits than its factorization.

644043 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11321.

The product of its (nonzero) digits is 1152, while the sum is 21.

The square root of 644043 is about 802.5228968696. The cubic root of 644043 is about 86.3584730565.

Adding to 644043 its reverse (340446), we get a palindrome (984489).

The spelling of 644043 in words is "six hundred forty-four thousand, forty-three".