644264771 has 2 divisors, whose sum is σ = 644264772. Its totient is φ = 644264770.

The previous prime is 644264741. The next prime is 644264779. The reversal of 644264771 is 177462446.

644264771 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 is a cyclic number.

It is not a de Polignac number, because 644264771 - 2²⁶ = 577155907 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (644264779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322132385 + 322132386.

It is an arithmetic number, because the mean of its divisors is an integer number (322132386).

Almost surely, 2^644264771 is an apocalyptic number.

644264771 is a deficient number, since it is larger than the sum of its proper divisors (1).

644264771 is an equidigital number, since it uses as much as digits as its factorization.

644264771 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 225792, while the sum is 41.

The square root of 644264771 is about 25382.3712643244. The cubic root of 644264771 is about 863.6838419969.

The spelling of 644264771 in words is "six hundred forty-four million, two hundred sixty-four thousand, seven hundred seventy-one".