644029 has 2 divisors, whose sum is σ = 644030. Its totient is φ = 644028.

The previous prime is 644009. The next prime is 644047. The reversal of 644029 is 920446.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 636804 + 7225 = 798^2 + 85^2 .

It is a cyclic number.

It is not a de Polignac number, because 644029 - 2¹¹ = 641981 is a prime.

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 643994 and 644012.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322014 + 322015.

It is an arithmetic number, because the mean of its divisors is an integer number (322015).

2⁶⁴⁴⁰²⁹ is an apocalyptic number.

It is an amenable number.

644029 is a deficient number, since it is larger than the sum of its proper divisors (1).

644029 is an equidigital number, since it uses as much as digits as its factorization.

644029 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 644029 is about 802.5141743297. The cubic root of 644029 is about 86.3578473078.

The spelling of 644029 in words is "six hundred forty-four thousand, twenty-nine".