644264741 has 2 divisors, whose sum is σ = 644264742. Its totient is φ = 644264740.

The previous prime is 644264669. The next prime is 644264771. The reversal of 644264741 is 147462446.

It is a happy number.

644264741 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., 366875716 + 277389025 = 19154^2 + 16655^2 .

It is a cyclic number.

It is not a de Polignac number, because 644264741 - 2¹⁴ = 644248357 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 644264695 and 644264704.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644264771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322132370 + 322132371.

It is an arithmetic number, because the mean of its divisors is an integer number (322132371).

Almost surely, 2^644264741 is an apocalyptic number.

It is an amenable number.

644264741 is a deficient number, since it is larger than the sum of its proper divisors (1).

644264741 is an equidigital number, since it uses as much as digits as its factorization.

644264741 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 129024, while the sum is 38.

The square root of 644264741 is about 25382.3706733630. The cubic root of 644264741 is about 863.6838285912.

The spelling of 644264741 in words is "six hundred forty-four million, two hundred sixty-four thousand, seven hundred forty-one".