644103 has 12 divisors (see below), whose sum is σ = 946920. Its totient is φ = 421776.

The previous prime is 644101. The next prime is 644107. The reversal of 644103 is 301446.

It is not a de Polignac number, because 644103 - 2¹ = 644101 is a prime.

644103 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644101) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 76 + ... + 1137.

It is an arithmetic number, because the mean of its divisors is an integer number (78910).

2⁶⁴⁴¹⁰³ is an apocalyptic number.

644103 is a deficient number, since it is larger than the sum of its proper divisors (302817).

644103 is a wasteful number, since it uses less digits than its factorization.

644103 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1278 (or 1275 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 644103 is about 802.5602781100. The cubic root of 644103 is about 86.3611547344.

Adding to 644103 its reverse (301446), we get a palindrome (945549).

It can be divided in two parts, 644 and 103, that added together give a palindrome (747).

The spelling of 644103 in words is "six hundred forty-four thousand, one hundred three".