644485229 has 2 divisors, whose sum is σ = 644485230. Its totient is φ = 644485228.

The previous prime is 644485213. The next prime is 644485271. The reversal of 644485229 is 922584446.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 550840900 + 93644329 = 23470^2 + 9677^2 .

It is a cyclic number.

It is not a de Polignac number, because 644485229 - 2⁴ = 644485213 is a prime.

It is a super-2 number, since 2×644485229² = 830722420798364882, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 644485229.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644485279) by changing a digit.

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

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322242614 + 322242615.

It is an arithmetic number, because the mean of its divisors is an integer number (322242615).

Almost surely, 2^644485229 is an apocalyptic number.

It is an amenable number.

644485229 is a deficient number, since it is larger than the sum of its proper divisors (1).

644485229 is an equidigital number, since it uses as much as digits as its factorization.

644485229 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 552960, while the sum is 44.

The square root of 644485229 is about 25386.7136313466. The cubic root of 644485229 is about 863.7823440968.

The spelling of 644485229 in words is "six hundred forty-four million, four hundred eighty-five thousand, two hundred twenty-nine".