644123 has 2 divisors, whose sum is σ = 644124. Its totient is φ = 644122.

The previous prime is 644117. The next prime is 644129. The reversal of 644123 is 321446.

It is a happy number.

644123 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a balanced prime because it is at equal distance from previous prime (644117) and next prime (644129).

It is a cyclic number.

It is not a de Polignac number, because 644123 - 2⁴ = 644107 is a prime.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 644095 and 644104.

It is not a weakly prime, because it can be changed into another prime (644129) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322061 + 322062.

It is an arithmetic number, because the mean of its divisors is an integer number (322062).

2⁶⁴⁴¹²³ is an apocalyptic number.

644123 is a deficient number, since it is larger than the sum of its proper divisors (1).

644123 is an equidigital number, since it uses as much as digits as its factorization.

644123 is an evil number, because the sum of its binary digits is even.

The product of its digits is 576, while the sum is 20.

The square root of 644123 is about 802.5727381366. The cubic root of 644123 is about 86.3620485900.

Adding to 644123 its reverse (321446), we get a palindrome (965569).

It can be divided in two parts, 644 and 123, that added together give a palindrome (767).

The spelling of 644123 in words is "six hundred forty-four thousand, one hundred twenty-three".