644937053 has 2 divisors, whose sum is σ = 644937054. Its totient is φ = 644937052.

The previous prime is 644937049. The next prime is 644937107. The reversal of 644937053 is 350739446.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 356378884 + 288558169 = 18878^2 + 16987^2 .

It is a cyclic number.

It is not a de Polignac number, because 644937053 - 2² = 644937049 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 644937053.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644937023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322468526 + 322468527.

It is an arithmetic number, because the mean of its divisors is an integer number (322468527).

Almost surely, 2^644937053 is an apocalyptic number.

It is an amenable number.

644937053 is a deficient number, since it is larger than the sum of its proper divisors (1).

644937053 is an equidigital number, since it uses as much as digits as its factorization.

644937053 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 272160, while the sum is 41.

The square root of 644937053 is about 25395.6109003111. The cubic root of 644937053 is about 863.9841518905.

The spelling of 644937053 in words is "six hundred forty-four million, nine hundred thirty-seven thousand, fifty-three".