644424629 has 2 divisors, whose sum is σ = 644424630. Its totient is φ = 644424628.

The previous prime is 644424581. The next prime is 644424647. The reversal of 644424629 is 926424446.

644424629 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 553660900 + 90763729 = 23530^2 + 9527^2 .

It is a cyclic number.

It is not a de Polignac number, because 644424629 - 2²⁰ = 643376053 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644424659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322212314 + 322212315.

It is an arithmetic number, because the mean of its divisors is an integer number (322212315).

Almost surely, 2^644424629 is an apocalyptic number.

It is an amenable number.

644424629 is a deficient number, since it is larger than the sum of its proper divisors (1).

644424629 is an equidigital number, since it uses as much as digits as its factorization.

644424629 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 331776, while the sum is 41.

The square root of 644424629 is about 25385.5200655807. The cubic root of 644424629 is about 863.7552698529.

The spelling of 644424629 in words is "six hundred forty-four million, four hundred twenty-four thousand, six hundred twenty-nine".