644352259 has 2 divisors, whose sum is σ = 644352260. Its totient is φ = 644352258.

The previous prime is 644352251. The next prime is 644352287. The reversal of 644352259 is 952253446.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 644352259 - 2³ = 644352251 is a prime.

It is not a weakly prime, because it can be changed into another prime (644352251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322176129 + 322176130.

It is an arithmetic number, because the mean of its divisors is an integer number (322176130).

Almost surely, 2^644352259 is an apocalyptic number.

644352259 is a deficient number, since it is larger than the sum of its proper divisors (1).

644352259 is an equidigital number, since it uses as much as digits as its factorization.

644352259 is an evil number, because the sum of its binary digits is even.

The product of its digits is 259200, while the sum is 40.

The square root of 644352259 is about 25384.0946066627. The cubic root of 644352259 is about 863.7229349058.

The spelling of 644352259 in words is "six hundred forty-four million, three hundred fifty-two thousand, two hundred fifty-nine".