644297833 has 2 divisors, whose sum is σ = 644297834. Its totient is φ = 644297832.

The previous prime is 644297783. The next prime is 644297861. The reversal of 644297833 is 338792446.

644297833 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., 643281769 + 1016064 = 25363^2 + 1008^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644297833 is a prime.

It is not a weakly prime, because it can be changed into another prime (644297333) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322148916 + 322148917.

It is an arithmetic number, because the mean of its divisors is an integer number (322148917).

Almost surely, 2^644297833 is an apocalyptic number.

It is an amenable number.

644297833 is a deficient number, since it is larger than the sum of its proper divisors (1).

644297833 is an equidigital number, since it uses as much as digits as its factorization.

644297833 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 870912, while the sum is 46.

The square root of 644297833 is about 25383.0225347574. The cubic root of 644297833 is about 863.6986157504.

The spelling of 644297833 in words is "six hundred forty-four million, two hundred ninety-seven thousand, eight hundred thirty-three".