644725253 has 2 divisors, whose sum is σ = 644725254. Its totient is φ = 644725252.

The previous prime is 644725217. The next prime is 644725261. The reversal of 644725253 is 352527446.

644725253 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., 469242244 + 175483009 = 21662^2 + 13247^2 .

It is a cyclic number.

It is not a de Polignac number, because 644725253 - 2²² = 640530949 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644725283) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322362626 + 322362627.

It is an arithmetic number, because the mean of its divisors is an integer number (322362627).

Almost surely, 2^644725253 is an apocalyptic number.

It is an amenable number.

644725253 is a deficient number, since it is larger than the sum of its proper divisors (1).

644725253 is an equidigital number, since it uses as much as digits as its factorization.

644725253 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 201600, while the sum is 38.

The square root of 644725253 is about 25391.4405459793. The cubic root of 644725253 is about 863.8895628770.

The spelling of 644725253 in words is "six hundred forty-four million, seven hundred twenty-five thousand, two hundred fifty-three".