644352223 has 2 divisors, whose sum is σ = 644352224. Its totient is φ = 644352222.

The previous prime is 644352209. The next prime is 644352251. The reversal of 644352223 is 322253446.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 644352223 - 2⁹ = 644351711 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644352523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322176111 + 322176112.

It is an arithmetic number, because the mean of its divisors is an integer number (322176112).

Almost surely, 2^644352223 is an apocalyptic number.

644352223 is a deficient number, since it is larger than the sum of its proper divisors (1).

644352223 is an equidigital number, since it uses as much as digits as its factorization.

644352223 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34560, while the sum is 31.

The square root of 644352223 is about 25384.0938975572. The cubic root of 644352223 is about 863.7229188203.

The spelling of 644352223 in words is "six hundred forty-four million, three hundred fifty-two thousand, two hundred twenty-three".